JP3537515B2 - Semiconductor photocathode and semiconductor photocathode device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor photocathode which emits electrons generated by the incidence of light by accelerating by applying a voltage from the outside.

[0002]

2. Description of the Related Art U.S. Pat. No. 3,958,143 discloses a photocathode which forms an electric field inside a semiconductor by an external bias voltage, transfers photoelectrons to an emission surface, and emits the electrons into a vacuum.
T. shown in the E. FIG. There is a photocathode. T. E. FIG. The operating mechanism of the photocathode is as described in several documents, and if briefly described, a III-V semiconductor (p.
^- ) By forming a Schottky electrode over the entire surface and applying a positive potential, an inclined electric field is formed inside the photocathode to form photoelectrons, accelerate the photoelectrons, and transition to the upper conduction band to cross the surface barrier. Release into vacuum. Regarding the optical response wavelength, it has been confirmed up to 2.1 μm and its effectiveness has been shown. Further, in order to improve the photoelectric conversion efficiency of the semiconductor photocathode, the efficiency of the Schottky electrode is improved by devising the shape of the Schottky electrode from the entire surface into a lattice shape.

Further, US Pat. No. 5,047,821 and Japanese Patent Application Laid-Open No. 4-269419 disclose techniques for manufacturing a semiconductor photocathode stably and with good reproducibility.

[0004]

However, the quantum efficiency of these semiconductor photocathodes is 0.1%, which is lower than that of ordinary photodetectors. Improvement in efficiency is desired. It is considered that this low quantum efficiency is caused by the capture of the photoelectrons on the Schottky electrode formed on the surface.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor photocathode capable of further improving quantum efficiency and a semiconductor photocathode device using the same.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a semiconductor photocathode and a semiconductor photocathode device (photodetector tube, photodetector, etc.) for emitting electrons generated in response to incident light by accelerating and emitting electrons by applying a voltage from outside. Image tubes, photomultiplier tubes, streak cameras, image intensifiers, etc.). And this semiconductor photocathode
a p-type first semiconductor layer (light-absorbing layer), a p-type second semiconductor layer (electron transport layer) formed on the first semiconductor layer, an opening, and a Schottky contact with the second semiconductor layer. And a third semiconductor layer having a work function smaller than the work function of the second semiconductor layer and formed in the opening of the Schottky electrode. An active layer) and a semiconductor portion (channel grating) having an energy band gap wider than that of the second semiconductor layer and extending on a line extending through the Schottky electrode in the thickness direction thereof and arranged inside the second semiconductor layer. Comprising the semiconductor part
The shape corresponds to the shape of the Schottky electrode with an opening
I decided to do it.

Further, as another configuration of such a semiconductor photocathode, a p-type first semiconductor layer, a p-type second semiconductor layer formed on the first semiconductor layer, and a p-type second semiconductor layer are formed. A semiconductor portion having a wide energy band gap, formed on the second semiconductor layer, and a Schottky electrode having an opening and formed so as to make a Schottky contact with the semiconductor portion and cover the surface of the semiconductor portion; has a smaller work function than the work function of the second semiconductor layer, a on an extension passing through the openings of the Schottky electrode in the axial direction, and a third semiconductor layer formed on the second semiconductor layer, said semiconductor The shape of the part
May correspond to the shape of the Schottky electrode .

The present invention is directed to a semiconductor photocathode device having such a semiconductor photocathode and an anode in an airtight container that provides an environment having a pressure lower than the atmospheric pressure therein. In this semiconductor photocathode device,
A semiconductor substrate, a p-type first semiconductor layer formed on the semiconductor substrate, a p-type second semiconductor layer formed on the first semiconductor layer, an opening, and a Schottky contact with the second semiconductor layer. And a third Schottky electrode having a work function smaller than the work function of the second semiconductor layer and formed in the opening of the Schottky electrode.
A semiconductor layer having an energy band gap wider than that of the second semiconductor layer and extending on a line extending through the Schottky electrode in the thickness direction thereof, and a semiconductor portion disposed inside the second semiconductor layer; A first connection pin that is electrically connected to and penetrates the sealed container; and a second connection pin that is electrically connected to the semiconductor substrate or the first semiconductor layer and penetrates the sealed container. The anode is electrically connected to the anode. It is connected, a third connecting pin penetrating the sealed container, the semiconductor
The shape of the body part is the shape of the Schottky electrode having an opening.
It is decided that it corresponds to .

This semiconductor photocathode device may include an electron multiplier disposed between the semiconductor photocathode and the anode, and the anode may be formed of a member containing a fluorescent substance. The electron multiplier includes a dynode or the like, and multiplies electrons output from the semiconductor photocathode and inputs the multiplied electrons to the anode. When the anode includes a member containing a fluorescent substance, the light input to the semiconductor photocathode is irradiated on the fluorescent substance to convert the incident light into fluorescent light and output from the semiconductor photocathode device. be able to.

[0010]

In the semiconductor photocathode of the present invention, first, a hole or electron pair is generated in the first semiconductor layer when light or an electromagnetic wave is incident on the p-type first semiconductor layer. At this time, the electrons are excited to the lower limit energy level (first energy level) of the gamma valley of the conduction band. Since a higher potential is applied to the Schottky electrode than to the first semiconductor layer, electrons generated by receiving a force from the electric field generated thereby travel toward the Schottky electrode. When the concentration of the second semiconductor layer is lower than that of the first semiconductor layer, a space charge region is generated in the second semiconductor layer in a wider range than the first semiconductor layer.
An electric field is generated in this space charge region, and the traveling electrons receive energy and receive a satellite valley (L or X) that is higher than the lower energy level of the gamma valley in the conduction band.
Valley) or a higher energy level of the gamma valley (second energy level) and travels toward the Schottky electrode.

On the other hand, a semiconductor portion having an energy band gap wider than that of the second semiconductor layer is disposed inside or on the surface of the second semiconductor layer on an extension extending through the Schottky electrode in the thickness direction. The trajectory of the traveling electron is bent by the potential barrier generated due to the existence of the portion, and the electron travels in the opening direction of the Schottky electrode. Since the third semiconductor layer is formed in the opening of the Schottky electrode or on an extension of the axis passing through the opening, electrons are introduced into the third semiconductor layer. The third semiconductor layer has a work function smaller than the work function of the second semiconductor layer, and electrons are easily emitted from the third semiconductor layer into a vacuum. The third semiconductor layer is made of, for example, a compound semiconductor mainly composed of an alkali metal having a low work function.
That is, as the material of the third semiconductor layer, Cs-O, C
s-I, Cs-Te, Sb-Cs, Sb-Rb-Cs,
Sb-K-Cs, Sb-Na-K, Sb-Na-K-C
Combinations such as s and Ag-O-Cs are listed.

Further, the semiconductor portion has an annular portion. If the area in the annular portion is smaller than the area in the opening of the Schottky electrode, electrons are efficiently opened by the semiconductor portion. Focused in the direction. Furthermore, if such a ring-shaped portion is combined to form a mesh shape, electrons can be emitted from the surface of the third semiconductor layer with high uniformity.

Further, in the semiconductor photocathode device formed by disposing the semiconductor photocathode and the anode in an airtight container, the potential of the first connection pin is set between the first connection pin and the second connection pin. A voltage is applied so as to be higher than the potential of the connection pin, and a voltage is applied between the second connection pin and the third connection pin so that the potential of the third connection pin is higher than the potential of the first connection pin. To use. In this state, the electrons emitted from the semiconductor photocathode are collected at the anode. Therefore, it is possible to extract a current corresponding to the light or electromagnetic wave incident from the third connection pin connected to the anode. A dynode or microchannel plate (MCP) for multiplying electrons emitted from the semiconductor photocathode is provided between the semiconductor photocathode and the anode.
May be further arranged.

In such a semiconductor photocathode device, the first semiconductor layer has an energy band near the interface between the first semiconductor layer and the semiconductor substrate in a region on the second semiconductor layer side in the first semiconductor layer. By providing the second graded layer having an energy band gap of an intermediate width between the gap and the energy band gap of the semiconductor substrate, the crystallinity at the interface between the semiconductor substrate and the p-type first semiconductor layer can be improved. It is possible to reduce the leakage current and the recombination current by holding the current.

Further, the second semiconductor layer is provided near the interface between the second semiconductor layer and the first semiconductor layer, in the third semiconductor layer in the second semiconductor layer.
The second semiconductor layer and the first semiconductor layer may have a first graded layer having an energy band gap intermediate between the energy band gap of the semiconductor layer side region and the energy band gap of the first semiconductor layer. , The crystallinity of the interface can be maintained well, and the leakage current and the recombination current can be reduced. Further, the semiconductor portion may include a semiconductor portion arranged in a stripe shape.
These semiconductor portions may include a first semiconductor portion (60a) and a second semiconductor portion (60d) crossing each other.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor photocathode according to the present invention will be described below with reference to the accompanying drawings. The same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a perspective view of a semiconductor photocathode according to the first embodiment.

The semiconductor photocathode CT of the present embodiment firstly
A p-type first semiconductor layer 20 (light absorbing layer) that generates electrons in response to the incidence of light is formed on a semiconductor substrate 10. The first semiconductor layer 20 has a first impurity concentration, and a second impurity concentration p-type second impurity having an impurity concentration lower than the first impurity concentration is formed on the first semiconductor layer 20.
A semiconductor layer 30 (electron transport layer) is formed. Further, a Schottky electrode 50 having a mesh shape or a lattice shape having an opening is formed so as to cover the surface of the second semiconductor layer 30. The Schottky electrode 50 is connected to the second
The Schottky contact is made with the semiconductor layer 30.

The surface of the second semiconductor layer 30 is
The third semiconductor layer 40 (active layer) is formed in the opening of the Schottky electrode 50. The third semiconductor layer 40 has a work function smaller than the work function of the second semiconductor layer 30. In the second semiconductor layer 30, a semiconductor portion 60 (channel lattice) having a third impurity concentration having an impurity concentration of about the second impurity concentration or less is buried.
The semiconductor unit 60 is provided on an extension extending through the Schottky electrode 50 in the thickness direction.

The semiconductor portion 60 has a mesh shape or a lattice shape, and an area in an annular portion defined by one lattice of the lattice shape is:
It is smaller than the area inside the opening of the Shotoki electrode 50. In addition,
The shape of the semiconductor portion 60 corresponds to the shape of the Schottky electrode. Thereby, the electrons are efficiently bent in the opening direction by the semiconductor portion 60, and the electrons are
Since 0 is a lattice shape, it is emitted from the surface of the third semiconductor layer with high uniformity. Note that an ohmic electrode 70 is provided on the p-type first semiconductor layer 20.

In this embodiment, the constituent materials and layer thicknesses of these semiconductor layers are set as follows.

The semiconductor substrate 10 is a (100) p-type InP semiconductor substrate, and the first semiconductor layer 20 has an impurity concentration of 1 × formed on the semiconductor substrate 10 by epitaxial growth.
It is a p-type InGaAs semiconductor of 10 ¹⁸ to 10 ²⁰ / cm ³ . The thickness of the first semiconductor layer 20 is determined by the electron diffusion length of this layer (for example, 1.5 to 2.5 μm).
Is appropriate. The p-type second semiconductor layer 30 has a thickness of 1.0 to
10 μm, p-type In with an impurity concentration of about 1 × 10 ¹⁷ / cm ³
The semiconductor portion 60 is a P semiconductor and has an impurity concentration of 1 × 10 ¹⁶
/ Cm ³ or less of p ^- is a AlAsSb semiconductor. Third
The semiconductor layer 40 is a (Cs · O) semiconductor having a work function smaller than the work function of the p-type second semiconductor layer 30.

The material of the third semiconductor layer is Cs
-O, Cs-I, Cs-Te, Sb-Cs, Sb-Rb
-Cs, Sb-K-Cs, Sb-Na-K, Sb-Na
Combinations of -K-Cs, Ag-O-Cs, and the like are listed. Note that the following substances can be selected as materials for these semiconductor layers. That is, [semiconductor substrate 10, p-type first
The combination of constituent materials of the semiconductor layer 20 (light absorbing layer), the p-type second semiconductor layer 30 (electron transport layer), and the semiconductor portion 60 (channel lattice)] is a combination of materials that can achieve lattice matching between the layers. It is appropriate, and it is desirable that the difference between the lattice constants of the respective layers is within ± 0.3%. Therefore, the range of such a combination of constituent materials is as shown in the following table.

[0024]

[Table 1]

Next, the operation of the semiconductor photocathode CT will be described. FIG. 2 is a cross-sectional view of the semiconductor photocathode CT of FIG. 1 taken along a line AA. Note that FIG. 3 shows an anode 90 provided to face the third semiconductor layer 40. As shown in the figure, a voltage (for example, 3.5 V) is applied between the ohmic electrode 70 and the Schottky electrode 50 so that the Schottky electrode 50 has a higher potential than the ohmic electrode 70. In addition, a voltage (for example, 100 V) is applied between the ohmic electrode 70 and the anode 90 so that the anode 90 has a higher potential than the ohmic electrode 70. Note that the semiconductor photocathode CT and the anode 90 are arranged in an environment of 10 ^-10 torr or less. The pressure of the environment in which the semiconductor photocathode CT and the anode 90 are arranged is at least a pressure equal to or lower than the atmospheric pressure from the viewpoint of electron emission and is 10 ⁻⁵ torr.
It is desirably not more than r.

When light or an electromagnetic wave is incident on the semiconductor photocathode CT under such conditions, first, the light or the electromagnetic wave is incident on the p-type first semiconductor layer 20 so that the first semiconductor layer 20 has a hole electron. A pair occurs. At this time, the electrons are excited to the lower limit energy level (first energy level) of the gamma valley of the conduction band. Since a higher potential is applied to the Schottky electrode 50 than the first semiconductor layer, the generated electrons travel toward the Schottky electrode 50 under the force of the electric field generated thereby. p-type second semiconductor layer 3
Since 0 has a lower concentration than the first semiconductor layer 20, an electric field stronger than the first semiconductor layer 20 is generated in the second semiconductor layer 30. The traveling electron receives energy due to this strong electric field, and receives energy from a satellite valley (L or X valley) higher than the lower energy level of the gamma valley in the conduction band or an energy level higher than the gamma valley (second energy). ) And travels in the direction of the Schottky electrode 50.

Here, inside the second semiconductor layer 30, the third line extends through the Schottky electrode 50 in the thickness direction thereof.
Since the semiconductor portion 60 having the impurity concentration is buried, the trajectory of the traveling electron is bent by the potential barrier generated due to the presence of the semiconductor portion 60, and the electron travels in the opening direction of the Schottky electrode 50. I do. Since the third semiconductor layer 40 is formed in the opening of the Schottky electrode 50, electrons are introduced into the third semiconductor layer 40. The third semiconductor layer 40 has a work function smaller than the work function of the second semiconductor layer 30, and electrons are easily emitted from the third semiconductor layer 40 into a vacuum. The emitted electrons receive a force in the direction of the anode 90 and travel in the direction of the anode 90.

Next, the traveling of electrons in the semiconductor photocathode CT will be described with reference to an energy band diagram.

FIG. 3A shows the semiconductor photocathode CT of FIG.
FIG. 3 is a plan view of a portion including a line segment AA and a line segment BB. Also, FIGS.
3A and 3B are energy band diagrams of the semiconductor photocathode CT taken along the line AA cross section and the line BB cross section in FIG. FIGS. 7B and 7C are energy band diagrams when no bias is applied to the semiconductor photocathode CT.

As is apparent from FIG.
Has a wider energy band gap than the second semiconductor layer 30, so that the energy level at the lower end of the conduction band Ec of the semiconductor portion 60 shifts more positively than the p-type second semiconductor layer. As a result, a potential barrier is formed inside the semiconductor photocathode CT, in which excited electrons do not easily travel toward the Schottky electrode 50.

Next, the behavior of electrons when a bias is applied to the semiconductor photocathode CT will be described with reference to FIG.

FIG. 4A shows the semiconductor photocathode CT of FIG.
FIG. 3 is a plan view of a portion including a line segment AA and a line segment BB. Also, FIGS.
3A and 3B are energy band diagrams of the semiconductor photocathode CT taken along the line AA cross section and the line BB cross section in FIG. FIG. 5 is an explanatory diagram for more easily explaining the behavior of the electrons shown in FIG.

As is apparent from FIG. 4C, even when a bias is applied, the semiconductor portion 60 has an energy band gap wider than that of the second semiconductor layer 30, so that the excited electrons E1 are generated. It functions as a potential barrier that does not easily travel in the direction of the Schottky electrode 50. Due to such a potential barrier, the electron E1 traveling in the second semiconductor layer 30 has its trajectory changed and travels in the direction of the third semiconductor layer 40 avoiding the semiconductor portion 60.

When a bias is applied to the Schottky electrode 50, the electron E1 is bent in the direction of the third semiconductor layer 40 formed in a region of the second semiconductor layer 30 where the Schottky electrode 50 is not formed. Can be That is, since the electron E1 passes through the region R between the semiconductor unit 60 and the semiconductor unit 60 adjacent to the semiconductor unit 60, the line segment AA
The density of the electron flow passing on the cross section will increase (see FIG. 5). When passing through the region R sandwiched between the semiconductor layers 60, as shown in FIG.
The electron E1 traveling in the second semiconductor layer 30 while being excited to the lower limit energy level of the gamma valley is accelerated by an electric field generated in the second semiconductor layer 30 to obtain energy. It is excited to a higher energy level in a satellite valley (L or X valley) or a gamma valley with a higher energy level than the level. After the electrons pass through the region R sandwiched between the semiconductor layers 60, the third semiconductor layer 40
Until it enters, the force in the direction of divergence acts on the electrons, but the distance between them is, for example, 0.5 to 2.0 μm,
Further, if the width between the semiconductor layer 60 and the Schottky electrode 50 is set so that the width of the semiconductor layer 60 ≧ the width of the Schottky electrode 50, the semiconductor substrate 10 and the first semiconductor
Most of the electrons E1 generated in the second semiconductor layer 30 enter the third semiconductor layer 40 without being absorbed by the Schottky electrode 50. The work function of the third semiconductor layer 40 is smaller than that of the second semiconductor layer 30, and the electrons E1 are efficiently emitted into a vacuum as shown in FIG. 4B and FIG.

FIG. 6 shows the semiconductor photocathode CT shown in FIG.
Is a perspective view showing a partially cutaway semiconductor photocathode device housed in a closed container.

The semiconductor photocathode device of the present invention has a pressure lower than the atmospheric pressure (10 ⁻⁵ torr or less, preferably 10 ⁻⁵ torr or less).
⁽ A pressure of ^-10 torr or less). The semiconductor photocathode CT has a first connection pin 1 and a second connection pin 2 electrically connected thereto, and the anode 90 has a third connection pin 90a electrically connected thereto.
have. The first connection pin 1, the second connection pin 2, and the third connection pin 90a penetrate the closed container 100.
An incident window 110 into which light or an electromagnetic wave is incident is arranged on the anode 90 side of the semiconductor photocathode CT. Entrance window 1
10 may be adhered to the container 100.

Such a semiconductor photocathode CT and anode 90
The semiconductor photocathode device formed by arranging the first connection pin 1 and the second connection pin 2 in the closed container 100 has the potential of the first connection pin 1 between the first connection pin 1 and the second connection pin 2 that is higher than the potential of the second connection pin 2. A voltage is applied so as to be higher, and a voltage is applied between the second connection pin 2 and the third connection pin 90a such that the potential of the third connection pin 90a is higher than the potential of the first connection pin 1. To use. The semiconductor photocathode C shown in FIG.
Referring to T, the Schottky electrode 50 and the ohmic electrode 70 are respectively formed of a metal 50a such as gold and a metal 7a.
The anode 90 has a third connection pin 90a connected to the first connection pin 1 and the second connection pin 2 via the first connection pin 0a.

Next, a method of manufacturing the semiconductor photocathode CT shown in FIG. 1 will be described.

FIG. 7 shows the semiconductor photocathode CT shown in FIG.
FIG. 6 is an explanatory diagram for describing the manufacturing method for the semiconductor photocathode CT using a cross-sectional configuration of the semiconductor photocathode CT.

First, a semiconductor substrate 10 is prepared. Then, the first semiconductor layer 20 and the second semiconductor layer 20 are formed on the semiconductor substrate 10.
Semiconductor 30a, semiconductor layer 60a and resist layer 200
a were sequentially laminated (FIG. 7A). Each semiconductor layer is laminated by MBE (molecular beam epitaxial growth) method, MOCVD
An epitaxial growth method such as (organic metal vapor phase epitaxy) is used.

Thereafter, the resist layer 200a was etched until it reached the semiconductor layer 60a from the surface to form a mesh-shaped resist 200 (FIG. 7B). next,
The semiconductor layer 60a was etched using the resist 200 as a mask to form a mesh-shaped semiconductor portion 60 (FIG. 7C). Thereafter, a material constituting the second semiconductor 30a is deposited on the second semiconductor 30a and the semiconductor unit 60 so as to cover the surfaces of the second semiconductor 30a and the semiconductor unit 60, thereby forming the second semiconductor layer 30 ( FIG.
(D)). Further, a Schottky electrode 50 was formed on the second semiconductor layer 30 so as to have the arrangement shown in FIG.
(E)). Next, the second semiconductor layer 30 is cleaned by heating it in an environment at a lower pressure than the atmosphere, and then the third semiconductor layer 40 is deposited so as to cover the Schottky electrode 50 and the second semiconductor layer 30. The semiconductor photocathode shown in FIG. 1 was obtained.

In this embodiment, the semiconductor substrate 10, the first semiconductor layer 20, and the second semiconductor layer 30 are made of InP, InGaAs, and InP, respectively, and have a thickness of 200.
nm resist film was used.

The impurity concentration (carrier concentration) of the first semiconductor layer 20 is p ⁺ (1 × 10 ¹⁸ to 1 × 10 ¹⁹ / cm ³ ). The thickness of the first semiconductor layer 20 is 1.5 to 2.5 μm
Is appropriate. The impurity concentration (carrier concentration) of the second semiconductor layer 30 is p ⁻ (1 × 10 ¹⁷ / cm ³ or less). The thickness of the second semiconductor layer 30 is suitably from 1.0 to 10 μm. The impurity concentration (carrier concentration) of the semiconductor unit 60 is p
^- (1 × 10 ¹⁷ to 1 × 10 ¹⁴ / cm ³ ). The thickness of the semiconductor portion 60 is suitably 0.5 to 2.0 μm.
The Schottky electrode 50 can be deposited on the second semiconductor layer 30 by a vacuum deposition method using a metal such as Al. In the present manufacturing method, the third semiconductor layer 40 is
s ₂ O, where Cs ₂ O is Cs (cesium) and O (oxygen)
, Or by alternately supplying a source gas containing these materials.

Incidentally, the p-type first semiconductor layer 20 of the semiconductor photocathode CT shown in FIG.
Near the interface between the first semiconductor layer 20 and the semiconductor substrate 10,
a second graded energy band gap having an intermediate width between the energy band gap of the first region 20a on the p-type second semiconductor layer 30 side in the p-type first semiconductor layer 20 and the energy band gap of the semiconductor substrate 10; Layer 20
b may be included. Thereby, in the present semiconductor photocathode CT1, the crystallinity at the interface between the semiconductor substrate 10 and the p-type first semiconductor layer 20 can be kept good, and the leak current and the recombination current can be reduced. The second semiconductor layer 3 is efficiently rebounded by the potential barrier.
It is led to 0.

The p-type second semiconductor layer 30 is provided near the interface between the p-type second semiconductor layer 30 and the p-type first semiconductor layer 20 in the third semiconductor layer 40 in the p-type second semiconductor layer 30. First graded layer 3 having an energy band gap of an intermediate width between the energy band gap of second region 30a on the side and the energy band gap of first semiconductor layer 20
Even if it has 0b, the crystallinity at the interface between the p-type second semiconductor layer 30 and the p-type first semiconductor layer 20 can be maintained well, and the leakage current and the recombination current can be reduced.

That is, the second graded layer 20b
Has a lattice constant intermediate between the lattice constant of the first region 20a and the lattice constant of the semiconductor substrate 10, and the first graded layer 3
0b has an intermediate lattice constant between the lattice constant of the second region 30a and the lattice constant of the first region 20a.

Although the ohmic electrode 70 is provided on the first semiconductor layer in the semiconductor photocathode CT shown in FIG. 1, it may be provided on the back surface of the semiconductor substrate 10 as shown in FIG. Good. Thus, the ohmic electrode 7
0 is set on the semiconductor substrate 10, the ohmic electrode 7 is compared with the semiconductor photocathode CT shown in FIG.
0 can be easily installed on the semiconductor substrate 10. Note that the present semiconductor photocathode CT2 may be provided with the second graded layer 20b and the first graded layer 30b similarly to the semiconductor photocathode CT1 shown in FIG.

The semiconductor photocathodes (CT, CT1 and CT1) described with reference to FIGS.
2) can be installed in the closed container 100 shown in FIG.

Next, a second embodiment of the semiconductor photocathode will be described with reference to FIGS. The material and impurity concentration of each semiconductor layer are the same as those of the semiconductor photocathode CT described with reference to FIG.

The semiconductor photocathode CT3 shown in FIG. 10 differs from the semiconductor photocathode CT shown in FIG. 3 in the position of the semiconductor portion 60 in the second semiconductor layer 30. That is, the semiconductor photocathode CT3 is formed by forming the p-type first semiconductor layer 20, the p-type second semiconductor layer 30, and the third semiconductor layer 4 on the semiconductor substrate 10.
0 are sequentially laminated, and the p-type second semiconductor layer 3 is formed.
A lattice-shaped semiconductor portion is embedded in 0. Then, the third semiconductor layer 4 on the buried semiconductor portion 60
The Schottky electrode 50 is formed on the surface where no 0 is formed. An ohmic electrode 70 is provided on the first semiconductor layer 20. These electrodes 50 and 70 are made of metal 50a such as gold and metal 7a, respectively.
0a is connected to a connection pin (not shown). The anode 90 is arranged to face the third semiconductor layer 40 and is connected to a connection pin (not shown). The semiconductor photocathode CT3 and the anode 90 are the same as those of the semiconductor photocathode CT shown in FIG.
It is set in 0.

FIG. 11 is an explanatory diagram for explaining a method of manufacturing the semiconductor photocathode CT3 shown in FIG. 10 using a cross section.

First, a semiconductor substrate 10 is prepared. Then, the first semiconductor layer 20, the second semiconductor 30a, the semiconductor layer 60a, and the resist layer 200a were sequentially stacked on the semiconductor substrate (FIG. 11A). The lamination of each semiconductor layer is M
The BE (molecular beam epitaxial growth) method was used. Then, the resist layer 200a is etched until it reaches the semiconductor layer 60a from the surface, and the mesh-shaped resist 20 is formed.
0 was formed (FIG. 11B). Next, this resist 2
The semiconductor layer 60a was etched by using 00 as a mask to form a mesh-shaped semiconductor portion 60 (FIG. 11C).
Thereafter, a material constituting the second semiconductor 30a is deposited on the second semiconductor 30a and the semiconductor unit 60 so as to cover the surfaces of the second semiconductor 30a and the semiconductor unit 60, thereby forming the second semiconductor layer 30 ( FIG. 11D). Next, the second semiconductor layer 30 was polished until the semiconductor portion 60 was exposed from its surface (FIG. 11E). Then, the semiconductor unit 60
An electrode was formed on the exposed surface of (2) (FIG. 11 (f)). Finally, the Schottky electrode 50 and the second semiconductor layer 3
The semiconductor photocathode CT3 shown in FIG. 10 was obtained by depositing the third semiconductor layer 40 so as to cover 0 (FIG. 11 (g)).

Next, a third embodiment of the semiconductor photocathode will be described with reference to FIG. The material and impurity concentration of each semiconductor layer are the same as those of the semiconductor photocathode CT described with reference to FIG.

FIG. 12 shows a semiconductor photocathode CT of this embodiment.
FIG. 4 is a sectional view taken along the thickness direction of FIG. In the semiconductor photocathode CT4, the semiconductor portion 60 provided in the second semiconductor layer 30 in the semiconductor photocathode CT shown in FIG.
It has a structure that makes contact with the second semiconductor layer 30 only on one surface. That is, the present semiconductor photocathode CT4
Is formed by sequentially stacking a p-type first semiconductor layer 20, a p-type second semiconductor layer 30, a third semiconductor layer 40, and a lattice-like semiconductor portion 60 on a semiconductor substrate 10. And
The third semiconductor layer 40 is formed so as to cover the surface of the second semiconductor layer 30, the semiconductor section 60, and the Schottky electrode. The first semiconductor layer 20 includes an ohmic electrode 70
Is provided. These electrode 50 and electrode 70
Are connected to connection pins (not shown) via a metal 50a such as gold and a metal 70a, respectively. Anode 90
Are arranged to face the third semiconductor layer 40, and are connected to connection pins (not shown). The semiconductor photocathode CT3 and the anode 90 are installed in a closed container 100 as shown in FIG. 6, similarly to the semiconductor photocathode CT shown in FIG.

In the semiconductor photocathode of the present embodiment, the semiconductor portion 60 can be formed without etching the second semiconductor layer 30 due to its structure. Therefore, the semiconductor photocathode is simpler than the semiconductor photocathode shown in FIGS. Not only can it be manufactured, but also deterioration of the crystallinity of the second semiconductor layer 30 due to etching can be prevented.

Next, another embodiment of the semiconductor photocathode will be described.

FIG. 13A is a plan view of a semiconductor photocathode according to this embodiment, and FIG. 13B is a plan view of FIG.
13C is a cross-sectional view of the semiconductor photocathode taken along the line AA ′, and FIG. 13C is a cross-section of the semiconductor photocathode taken along the line BB ′ in FIG. FIG.

The semiconductor photocathode is connected to the semiconductor substrate 31.
0, the first semiconductor layer 32 formed on the semiconductor substrate 310
0, the second semiconductor layer 3 formed on the first semiconductor layer 320
30, a third semiconductor layer (active layer) 340 formed on the second semiconductor layer 330, a semiconductor section 360 embedded in the second semiconductor layer 330, and a Schottky electrode 350 formed on the second semiconductor layer 330. Have. More specifically, a p-type first semiconductor layer 320 (light absorbing layer) that generates electrons in response to light incidence is formed on the semiconductor substrate 310. This first semiconductor layer 320 has a first impurity concentration. On this first semiconductor layer 320, a p-type second semiconductor layer 330 (electron transport layer) having a second impurity concentration having an impurity concentration lower than the first impurity concentration is formed. Then, a stripe-shaped (comb-shaped) Schottky electrode 350 is formed so as to cover the surface of the second semiconductor layer 330. That is, the Schottky electrode 350 includes a stripe-shaped semiconductor portion. Schottky electrode 35
0 is in Schottky contact with the second semiconductor layer 330.

On the surface of the second semiconductor layer 330, there is a third gap between the stripe-shaped Schottky electrodes 350.
A semiconductor layer 340 (active layer) is formed. This third
The semiconductor layer 340 has a work function smaller than the work function of the second semiconductor layer 330. In the second semiconductor layer 330, a semiconductor portion 360 (channel lattice) having a third impurity concentration having an impurity concentration of about the second impurity concentration or lower is buried. The semiconductor section 360 is provided on an extension extending through the Schottky electrode 350 in the thickness direction. The semiconductor section 360 according to the present embodiment has a stripe shape. When light is incident on the semiconductor photocathode, electrons generated in the semiconductor photocathode are converted into the first semiconductor layer 32 by an electric field in the semiconductor photocathode.
It runs from 0 to the active layer 340. Second semiconductor layer 33
Since the comb-shaped semiconductor portion 360 is embedded in 0, the electrons are efficiently bent in the gap direction of the stripe 350 by the semiconductor portion 360. Since the active layer 340 is disposed in the gap between the stripes 350, the electrons are emitted from the surface of the third semiconductor layer 340 with high uniformity. The semiconductor substrate 310 includes the substrate 3
Ohmic electrode 370 for applying a bias to
Is installed.

Next, another embodiment of the present invention will be described. FIG. 14 is a perspective view showing the semiconductor photocathode according to the example, partially cut away. This semiconductor photocathode is different from the Schottky electrode 50 shown in FIG.
0b... Since the Schottky electrode 50a and the Schottky electrode 50b are electrically insulated, a potential independent of the Schottky electrode 50b can be applied to the electrode 50a. Note that other elements (10, 2)
0, 30, 40, 60, and 70) are the same as the elements shown in FIG.

Next, another embodiment of the present invention will be described. FIG. 15 is a perspective view showing the semiconductor photocathode according to the present embodiment in a partially broken manner. FIG. 16A shows the state of FIG.
FIG. 16B is a plan view of the semiconductor photocathode shown in FIG.
FIG. 17B is a cross-sectional view of the semiconductor photocathode of FIG. 16A taken along a line AA ′. FIG.
In FIG. 6A, the active layer 40 shown in FIG. 16B is omitted for easy understanding of the structure of the semiconductor photocathode. This semiconductor photocathode is shown in FIG.
The lead electrodes 50a 'and 50b' are connected to the Schottky electrodes 50a and 50b shown in FIG. The terminal portion of the lead electrode 50a 'constitutes a terminal for applying a potential to the Schottky electrode 50a,
The terminating end of ′ constitutes a terminal for applying a potential to the Schottky electrode 50b. Electrode 50a and electrode 50
b and the electrode 50c and the electrode 50d are provided with a lead electrode, and the lead electrode 50a 'or 50b
Does not hinder the passage of the electrons emitted from the active layer 40. In addition, other elements (10, 20, 30, 40,
The constituent materials and impurity concentrations of (60, 70) are the same as the elements shown in FIG.

Next, another embodiment of the present invention will be described. FIG. 17A is a plan view of the semiconductor photocathode, and FIG. 17B is a cross-section of the semiconductor photocathode taken along the line BB ′ of FIG. FIG. In FIG. 17A, the active layer 40 shown in FIG. 17B is omitted for easy understanding of the structure of the semiconductor photocathode. This semiconductor photocathode includes the position of the semiconductor portion 60 of the semiconductor photocathode shown in FIGS.
The position of 50b is changed. Second semiconductor layer 3
The semiconductor portion 60 is buried in 0. Semiconductor section 6
The Schottky electrodes 50a to 50d are formed directly on the surface of the zero. Each Schottky electrode 50a-50d
Of the active layer 40 on the second semiconductor layer
Is formed. The semiconductor photocathode having this structure has the advantages that electrons can be independently emitted from each of the pixels 50a to 50d, and the manufacturing method is simple as described with reference to FIG. The elements (10, 20, 30, 40, 50a, 50b, 60, 7
The constituent material and impurity concentration of 0) are the same as the elements shown in FIG.

Next, another embodiment of the present invention will be described. FIG. 18A is a plan view of the semiconductor photocathode, and FIG. 18B is a cross-section of the semiconductor photocathode of FIG. 18A taken along a line CC ′. FIG. In FIG. 18A, the active layer 40 shown in FIG. 18B is omitted for easy understanding of the structure of the semiconductor photocathode. This semiconductor photocathode includes the position of the semiconductor portion 60 of the semiconductor photocathode shown in FIGS.
The position of 50b is changed. Second semiconductor layer 3
The semiconductor portion 60 is buried in 0. Semiconductor section 6
The Schottky electrodes 50a to 50d are formed directly on the surface of the zero. Each Schottky electrode 50a-50d
The active layer 40 is formed within the opening and on the second semiconductor layer. The semiconductor photocathode of this structure can emit electrons independently from each of the pixels 50a to 50d by applying a potential to each of the electrodes 50a to 50d, and as described with reference to FIG. Has the advantage of being simple. Note that the element (1
0, 20, 30, 40, 60, 70) are the same as the elements shown in FIG.

Next, control of electron emission in the semiconductor photocathode shown in FIGS. 15 and 16 will be described. Hereinafter, the “accumulation mode” in which electrons enter the semiconductor photocathode when light enters the semiconductor photocathode and the “emission mode” in which electrons are emitted will be described.

(Accumulation Mode) FIG. 19A is a sectional view of a semiconductor photocathode device in which an anode 90 is connected to the semiconductor photocathode shown in FIGS. In the figure, the electrode 70 is attached to the semiconductor substrate 10, and reference numerals 901, 902, and 501 represent ohmic electrodes. A power supply V is provided between the electrode 70 and the anode 90.
₁ is connected, and the potential of the anode 9 is higher than the potential of the electrode 70.
The zero potential is V ₁ (volts) higher. Electrode 70 and the Schottky electrode 50c, 50d is connected to the power supply V ₂ between the Schottky electrode 50c than the potential of the electrode 70, 50
The potential of d is higher by V ₂ (volt). The potential V ₂ is the potential V
Lower than _1, the voltage source V ₂ is variable. Here, the Schottky electrode 50c and the Schottky electrode 50d
Are connected to each other, and a common potential is applied to these electrodes 50c and 50d.

FIG. 19B is a sectional view taken along line XX ′ of FIG.
It is an energy band diagram of a semiconductor photocathode line connecting (V ₂ = 0 to 1 volts). Light hν is applied to the first semiconductor layer 20.
Is incident, the electrons e generated in the first semiconductor layer 20 enter the second semiconductor layer 30 by receiving a force from the electric field inside the first semiconductor layer 20. FIG. 19 (a)
The region above the one-dot chain line (on the drawing) is the semiconductor portion 60
This is a depletion region formed by a concentration difference between the second semiconductor layer 30 and the second semiconductor layer 30. Therefore, the first semiconductor layer 20 to the active layer 4
The path of electrons in the zero direction is cut by this air space area (pinch-off state).

FIG. 19C is a sectional view taken along the line YY ′ of FIG.
It is an energy band diagram of a semiconductor photocathode line connecting (V ₂ = 0 to 1 volts). FIG. 19 (b) and FIG.
As shown in (c), the electrons e generated in the first semiconductor layer 10 are accumulated in the second semiconductor layer 30.

(Emission Mode) FIG.
It is an energy band diagram of a semiconductor photocathode line connecting the X-X'of (a) (V ₂ = 2~ number 10 volts). In this way, the electrons e accumulated in the second semiconductor layer 30 are emitted from the semiconductor photocathode by applying a voltage of 2 to several tens of volts between the Schottky electrode 50c and the electrode 70.

FIG. 20 is a sectional view of a semiconductor photocathode device using the semiconductor photocathode shown in FIG. A sealed container (inner case) CA2 made of a transparent material is fitted on the inner wall of the cylindrical outer case CA1 made of a light shielding material. A lens L1 is fixed near the opening of the outer case CA1. Light input into the semiconductor photocathode device from outside the semiconductor photocathode device is condensed by the lens L1 and forms an image on the semiconductor photocathode CT5 arranged in the closed container CA2. Voltage source V ₂ is connected between the electrode 70 and the lead electrode 50c of the semiconductor photocathode CT. In the closed container CA2, a two-dimensional image sensor IM responsive to incident electrons is arranged. The two-dimensional image sensor IM is a device that extracts electrons input from the surface of the image sensor IM from the lead wire RE4. The image sensor IM includes a layer IM2 sensitive to incident electrons and a back contact IM1 provided on the back surface of the layer IM2, and a lead RE2 is connected to the back contact IM1. Lead R
Between the E2 and leads RE1, it is connected to the voltage source V _1, the lead RE1 since the electrode 70 is connected, electrons emitted from the semiconductor photocathode CT5 proceeds to anode IM direction. The pressure in the closed container is lower than the atmospheric pressure, is 10 ^-5 torr or less, and desirably 10 ^-10 torr or less. Therefore, light input to the semiconductor photocathode device (weak light detection tube) from the left side of the drawing can be detected as an electric signal. Note that a microchannel plate may be disposed between the cathode CT5 and the anode IM.

As described above, the semiconductor photocathode according to the present invention can be applied to a device for detecting light. Although the image tube using the semiconductor photocathode has been described above, it can be applied to an electron multiplier or a streak camera. That is, in a device using a semiconductor photocathode, a microchannel plate (MCP), a dynode or a secondary electron multiplier may be provided between the anode and the cathode, and a deflection electrode for deflecting the electron trajectory is provided on the anode. And a cathode. Further, a fluorescent member coated with a fluorescent paint may be used for the anode,
A fluorescent plate containing a fluorescent material may be used.

[0071]

As described above, according to the present invention, since the semiconductor portion is disposed inside or on the surface of the second semiconductor layer, electrons travel in the direction of the opening of the Schottky electrode. Since the third semiconductor layer is formed in the opening of the Schottky electrode or on an extension of the axis passing through the opening, the electrons are transferred to the third semiconductor layer.
Introduced into the semiconductor layer. As described above, since the electrons are emitted from the third semiconductor layer into the vacuum avoiding the Schottky electrode, the ratio of absorption of the electrons by the Schottky electrode is reduced. Therefore, the amount of electrons collected at the anode increases with respect to the energy of the incident light, and the semiconductor photocathode using such a semiconductor photocathode can maintain high detection sensitivity. Further, by arranging the semiconductor portion, the aperture ratio is 100%, the pixel separation in the structure becomes unnecessary, and the signal can be modulated.

[Brief description of the drawings]

FIG. 1 is a perspective view of a semiconductor photocathode according to a first embodiment.

FIG. 2 is a sectional view of the semiconductor photocathode CT of FIG.
It is sectional drawing cut | disconnected along A.

FIG. 3 is a plan view (a) showing a portion including a line segment AA and a line segment BB of the semiconductor photocathode CT shown in FIG. 1, and a sectional view taken along line AA of FIG. Energy band diagram of semiconductor photocathode CT (b) and line segment B−
It is an energy band figure (c) of the semiconductor photocathode CT in B section. FIGS. 7B and 7C are energy band diagrams when no bias is applied to the semiconductor photocathode CT.

FIG. 4 is a plan view (a) showing a portion including a line segment AA and a line segment BB of the semiconductor photocathode CT shown in FIG. 1, and a sectional view taken along line AA in FIG. Band diagram (b) and line segment B of the semiconductor photocathode CT in FIG.
It is an energy band figure (c) of the semiconductor photocathode CT on the -B cross section. It is to be noted that FIGS.
3 is an energy band diagram when a bias is applied to the semiconductor photocathode CT.

FIG. 5 is an explanatory diagram for more easily explaining the behavior of the electrons shown in FIG. 4;

FIG. 6 is a perspective view showing a partially cutaway semiconductor photocathode device in which the semiconductor photocathode CT shown in FIG. 1 is housed in a closed container.

FIG. 7 is an explanatory diagram for describing a method of manufacturing the semiconductor photocathode CT shown in FIG. 1 using a cross-sectional configuration of the semiconductor photocathode CT.

FIG. 8 is a cross-sectional view showing another configuration of the semiconductor photocathode according to the first embodiment, using a cross section cut in a thickness direction.

FIG. 9 is a cross-sectional view showing another configuration of the semiconductor photocathode according to the first example, using a cross section cut in a thickness direction.

FIG. 10 is a cross-sectional view of a semiconductor photocathode CT3 of a second embodiment cut in a thickness direction.

11 is an explanatory diagram for describing a method of manufacturing the semiconductor photocathode CT3 illustrated in FIG. 10 using a cross section.

FIG. 12 is a sectional view of a semiconductor photocathode CT4 of a third embodiment cut in a thickness direction.

13A is a plan view of a semiconductor photocathode according to a fourth embodiment, FIG. 13B is a cross-sectional view taken along a line AA ′ in FIG. 13A, and FIG. It is sectional drawing cut | disconnected along line BB '.

FIG. 14 is a perspective view showing a semiconductor photocathode according to a fifth embodiment with a part thereof broken away.

FIG. 15 is a perspective view showing the semiconductor photocathode of the sixth embodiment with a part cut away.

16A is a plan view of the semiconductor photocathode shown in FIG. 15, and FIG. 16B is a cross-sectional view taken along line AA ′ of FIG.

17A is a plan view of a semiconductor photocathode according to a seventh embodiment, and FIG. 17B is a cross-sectional view taken along line BB ′ of FIG.

18A is a plan view of the semiconductor photocathode of the eighth embodiment, and FIG. 18B is a cross-sectional view taken along line CC ′ of FIG.

FIG. 19 is a sectional view (a) of a semiconductor photocathode and an anode,
The energy band diagram (b) along the line XX 'in FIG. 5A, the energy band diagram along the line YY' (electron accumulation) in FIG. , An energy band diagram along the line YY ′ in FIG.
(D).

FIG. 20 is a sectional view of a semiconductor photocathode device on which the semiconductor photocathode CT5 is mounted.

[Explanation of symbols]

10 semiconductor substrate, 20 first semiconductor layer, 30 second semiconductor layer, 40 third semiconductor layer, 50 Schottky electrode,
Reference numeral 60: semiconductor part, 70: ohmic electrode, 90: anode.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 1/34 H01J 1/308 H01J 1/35 H01J 1/78 H01J 29/38 H01J 40/06

Claims (11)

(57) [Claims] 1. A semiconductor photocathode which accelerates and emits electrons generated in response to incident light by applying a voltage from the outside, comprising: a first p-type semiconductor layer; A Schottky electrode having an opening, forming an Schottky contact with the second semiconductor layer so as to cover the surface of the second semiconductor layer, A second semiconductor layer having a work function smaller than the work function of the second semiconductor layer, a third semiconductor layer formed in the opening of the Schottky electrode, and a wider energy band gap than the second semiconductor layer; A semiconductor portion disposed on an extension line penetrating in a thickness direction and disposed inside the second semiconductor layer, wherein the semiconductor portion has an opening.
A semiconductor photocathode characterized by having a shape corresponding to a pole . 2. A semiconductor photocathode which accelerates and emits electrons generated in response to incident light by applying a voltage from the outside, comprising: a p-type first semiconductor layer; A second p-type semiconductor layer formed on the second semiconductor layer, a semiconductor portion having an energy bandgap wider than the second semiconductor layer, a semiconductor portion formed on the second semiconductor layer, and an opening, A Schottky electrode formed to cover the surface of the semiconductor portion by making Schottky contact with the second semiconductor layer, and having a work function smaller than the work function of the second semiconductor layer, and penetrating the opening of the Schottky electrode in the axial direction. On an extension of the second
A third semiconductor layer formed on the semiconductor layer, wherein the semiconductor portion has an opening.
A semiconductor photocathode characterized by having a shape corresponding to a pole . 3. The semiconductor device according to claim 1, wherein the semiconductor portion has an annular portion, and an area in the annular portion is smaller than an area in the opening of the Schottky electrode.
Or the semiconductor photocathode according to claim 2. 4. The semiconductor photocathode according to claim 3, wherein said semiconductor portion has a mesh shape. 5. The semiconductor device according to claim 5, wherein the second semiconductor layer has an energy band gap near an interface between the second semiconductor layer and the first semiconductor layer in a region on the third semiconductor layer side in the second semiconductor layer. A first semiconductor layer having an energy band gap intermediately wide from the energy band gap of the first semiconductor layer;
The semiconductor photocathode according to claim 1, further comprising a graded layer. 6. The semiconductor photocathode according to claim 1, wherein the semiconductor portion includes a semiconductor portion arranged in a stripe shape. 7. A semiconductor photocathode device comprising: a semiconductor photocathode and an anode disposed in an airtight container that provides an environment having a pressure lower than the atmospheric pressure therein, wherein the semiconductor photocathode includes: a semiconductor substrate; A p-type first semiconductor layer formed on the semiconductor substrate, a p-type second semiconductor layer formed on the first semiconductor layer, and an opening;
A Schottky electrode formed to cover the surface of the second semiconductor layer by making Schottky contact with the second semiconductor layer; and a work function smaller than the work function of the second semiconductor layer; A third semiconductor layer formed in the opening, having an energy band gap wider than the second semiconductor layer, and extending on a line extending through the Schottky electrode in a thickness direction thereof, inside the second semiconductor layer; A semiconductor portion disposed, a first connection pin electrically connected to the Schottky electrode and penetrating the sealed container; and a first connection pin electrically connected to the semiconductor substrate or the first semiconductor layer and penetrating the sealed container. comprising a second connecting pin, and the anode is electrically connected to the anode, and a third connecting pin penetrating the closed vessel, the shape of the semiconductor unit, before having an opening Schottky power
A semiconductor photocathode device, which corresponds to the shape of a pole . 8. The semiconductor substrate according to claim 1, wherein the first semiconductor layer has an energy band gap near an interface between the first semiconductor layer and the semiconductor substrate in an area on the second semiconductor layer side in the first semiconductor layer. 8. The semiconductor photocathode device according to claim 7, further comprising a second graded layer having an energy band gap that is intermediate between the energy band gap and the second graded layer. 9. The semiconductor photocathode device according to claim 7, wherein the semiconductor photocathode device includes an electron multiplier disposed between the semiconductor photocathode and the anode. 10. The semiconductor photocathode device according to claim 7, wherein the anode includes a member containing a fluorescent substance. 11. A semiconductor photocathode device comprising: a semiconductor photocathode and an anode disposed in a sealed container providing an environment having a pressure lower than the atmospheric pressure therein, wherein the semiconductor photocathode comprises: a semiconductor substrate; A p-type first semiconductor layer formed on a semiconductor substrate; a p-type second semiconductor layer formed on the first semiconductor layer; and a p-type second semiconductor layer disposed between the second semiconductor layer and the anode. A Schottky electrode, a third semiconductor layer having a work function smaller than the work function of the second semiconductor layer, and disposed between the second semiconductor layer and the anode, and a wider energy than the second semiconductor layer. A semiconductor portion having a band gap, disposed on an extension extending through the Schottky electrode in the thickness direction thereof, and electrically connected to the Schottky electrode; and a semiconductor portion formed on the second semiconductor layer. , The closed container A first connection pin penetrating therethrough, and a second connection pin electrically connected to the semiconductor substrate or the first semiconductor layer and penetrating the sealed container, wherein the anode is electrically connected to the anode, A third connection pin penetrating the airtight container, wherein the shape of the semiconductor portion is the Schottky electrode having an opening;
A semiconductor photocathode device, which corresponds to the shape of a pole .