KR101155412B1

KR101155412B1 - Photodetector included MicroChannelPlate, Method for Detecting Photo, Analysis system for analyzing sample and Method thereof

Info

Publication number: KR101155412B1
Application number: KR20100099582A
Authority: KR
Inventors: 김정원
Original assignee: 한국표준과학연구원
Priority date: 2010-10-13
Filing date: 2010-10-13
Publication date: 2012-07-03
Also published as: KR20120038058A

Abstract

The present invention relates to a photodetector having a microchannel plate, a sample analysis system using the photodetector, a photodetection method and a sample analysis method using the photodetector. More specifically, a photodetector for scanning light emitted from a sample by scanning an electron beam to the sample with an electron gun, comprising: a window composed of SrF ₂ through which light emitted from the sample is transmitted to emit transmitted light; A microchannel plate to which the transmitted light emitted from the window is incident and is provided in a chevron pattern and emits secondary electrons in the form of pulses; A voltage applying unit for accelerating secondary electrons by applying a high voltage of about 2 kV to the microchannel plate; A coating layer formed on one side of the microchannel plate on which transmitted light is incident and composed of KBr for inducing emission of secondary electrons; A shield provided with a window and a micro channel plate therein in the form of a hollow tube; A grid provided to be spaced apart from one side of the window from which light is scanned at a predetermined interval to control the light to be scanned such that the window does not become an anode or a cathode; And a detecting means for detecting secondary electrons in the form of pulses emitted from the microchannel plate.

Description

Photodetector included MicroChannel Plate, Method for Detecting Photo, Analysis system for analyzing sample and Method

The present invention relates to a photodetector having a microchannel plate, a sample analysis system using the photodetector, a photodetection method and a sample analysis method using the photodetector. More specifically, a window composed of SrF ₂ and a coating layer composed of KBr are stacked, and more light is incident, including a micro channel plate having a chevron pattern, thereby shortening the measurement time and reducing the pulse wave type secondary electrons. The present invention relates to a photodetector capable of detection, a photodetection method using the photodetector, and an analysis system and method of a sample.

Photodetectors are used to detect light emitted from a sample by scanning an electron beam through the sample with an electron gun to analyze a sample such as a metal or a semiconductor. One example of a photodetector in the prior art is to use a photo-electron multiplier. First, FIG. 1 is a perspective view schematically showing a photodetector using a photoelectron multiplier.

As shown in FIG. 1, an electron beam (not shown in FIG. 1) is incident by an electron gun (not shown in FIG. 1), and the light 2 emitted from a sample (not shown in FIG. 1) is a conventional photodetector ( Incident to 1). The emitted light 2 is transmitted through a single crystal window 3, one side of which is laminated with the KCL thin film 4). In order to converge and enter the emitted light 2 window 3 in a desired direction, a path of light may be adjusted using a mirror (not shown).

The transmitted light transmitted through the window 3 is incident on the photoelectron multiplier 5. The photoelectron multiplier 5 has a hollow tube shape in which the other side is closed, and an inner diameter is provided to about 1 cm or less. The light incident on the photoelectron multiplier 5 is incident on a dynode 6 formed in a tube shape and is emitted to the photoelectron 7. The emitted optoelectronics 7 are amplified by electrodes 8 consisting of a plurality of stages to emit secondary electrons, and the intensity is increased by the amplifier 10 via a collector 9, thereby increasing the pulse counter. The sample is analyzed by observing the secondary electrons emitted by the pulse counter circuit (11). Here, the window 3 serves as a low pass filter, and the photoelectron multiplier 5 serves as a high pass filter.

However, in the conventional photodetector 1 using such a photoelectron multiplier 5, the diameter of the inner diameter to which the light 2 is incident is limited to about 1 cm or less, so that a lot of light 2 cannot enter. exist. Therefore, since the incident light 2 is limited, the signal for light is also limited. Therefore, the time required to detect and measure the light to obtain information about the sample takes about 1 hour. In addition, this drawback requires a lot of manpower consumption for measurement because the electron gun must be controlled to take a spectrum while changing the photon energy emitted from the sample.

Therefore, the present invention has been made to solve the above problems, according to one embodiment of the present invention, the window and the micro channel plate can be provided in the form of a wafer to increase the solid angle. Therefore, more light emitted from the sample can be incident, so that a signal for a large amount of light can be secured in a short time. Therefore, the measurement time can be shortened by about 1/10 compared with the conventional photodetector.

In addition, the microchannel plate is provided with a KBr coating layer, and a high voltage can be applied by the voltage applying unit to emit pulse-shaped secondary electrons, so that the sample can have various states such as electron state, orbital state, electron occupation, and non-occupancy energy. Information can be obtained accurately.

In addition, an embodiment of the present invention, including the shield to block the effect of the high voltage applied to the electron gun, to prevent other electrons from entering the sample, the signal output by the electrons other than the signal by the light emitted from the sample It provides a photodetector that can prevent the.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings.

A first object of the present invention is a photodetector for detecting light emitted from a sample by scanning an electron beam through the sample with an electron gun, comprising: a window composed of SrF ₂ through which light emitted from the sample is transmitted to emit transmitted light; A microchannel plate to which transmitted light emitted from the window is incident to emit pulsed secondary electrons; And detection means for detecting secondary electrons in the form of pulses emitted from the microchannel plate. It can be achieved with a photodetector having a microchannel plate.

The method may further include a voltage applying unit for accelerating secondary electrons by applying a voltage to the microchannel plate.

The voltage applied to the microchannel plate by the voltage applying unit may be characterized in that 1700 ~ 2500V.

It may be characterized in that it further comprises a coating layer provided on one side of the microchannel plate to which the transmitted light is incident to induce the emission of secondary electrons.

The thickness of the coating layer may be characterized in that 2500 ~ 3500Å.

The coating layer may be characterized in that composed of KBr.

The microchannel plate may be provided with a chevron pattern.

The thickness of the window may be 1.5 to 2.5mm.

It may be characterized in that it further comprises a shield having a window and a micro channel plate therein in the form of a hollow tube.

The inner diameter of the shield can be characterized in that 25 to 70 mm.

In addition, the shield may be characterized in that it serves to block the electromagnetic field inside the detector from the outside.

The light may be further provided to be spaced apart from one side of the window to be scanned at a predetermined interval to control the light to be scanned so that the window is not charged to the anode or cathode.

It may be characterized in that it further comprises a positive electrode plate connected to the detection means and the secondary electrons accelerated by the voltage applied by the voltage applying unit is amplified and converges and discharges the secondary electrons in the form of pulse waves.

According to a second aspect of the present invention, in a sample analysis system using a photodetector, the analysis means connected to the detection means included in the photodetector receives the secondary electrons in the form of pulse waves detected by the detection means and analyzes the sample information. It can be achieved by a sample analysis system using a photodetector having a micro-channel plate comprising a.

The analyzing means may analyze the secondary electrons to obtain at least one of the electronic state of the sample, the orbital state of the sample, the electron occupancy state of the sample, and the non-electronic occupancy state of the sample.

A third object of the present invention is a photodetection method using a photodetector, the method comprising: scanning an electron beam onto a sample by an electron gun to emit light having a specific photon energy in the sample; The emitted light is transmitted through a window composed of SrF ₂ to emit transmitted light;

Transmitted light is incident on the microchannel plate to emit pulsed secondary electrons; And detecting the secondary electrons by the detection means.

The secondary electron emission step may further include accelerating the secondary electrons by applying a voltage to the microchannel plate by the voltage applying unit.

The secondary electron emission step may further include inducing emission of secondary electrons by a coating layer composed of KBr provided on one side of the microchannel plate.

Before the transmitted light emitting step, it may be characterized in that it further comprises the step of adjusting the light so that the window does not become an anode or a cathode by a grid provided spaced apart at a predetermined interval on one side of the window is scanned light.

Secondary electrons accelerated by a voltage applied by the voltage applying unit may be further amplified by the positive electrode plate to transmit secondary electrons in the form of pulse waves to the detection means.

According to a fourth aspect of the present invention, there is provided a method for analyzing a sample using a photodetector, comprising: scanning an electron beam onto a sample by an electron gun to emit light having a specific photon energy from the sample; The emitted light is transmitted through a window composed of SrF ₂ to emit transmitted light; Inducing emission of secondary electrons by a coating layer composed of KBr provided on one side of the microchannel plate, and transmitted light is incident on the microchannel plate to emit secondary electrons in the form of pulse waves; Detecting secondary electrons by the detection means; And analyzing the detected pulse wave secondary electrons in analysis means connected to the detection means to obtain information about the sample.

Therefore, as described above, according to the exemplary embodiment of the present invention, the window and the microchannel plate are provided in the form of a wafer, thereby increasing the solid angle. Accordingly, there is an advantage that the light emitted from the sample can be incident more, thereby ensuring a signal for a large amount of light in a short time. Therefore, the measurement time can be shortened to about 1/10 as compared with the conventional photodetector. In addition, the microchannel plate is provided with a KBr coating layer, and a high voltage can be applied by the voltage applying unit to emit pulse-shaped secondary electrons, so that the sample can have various states such as electron state, orbital state, electron occupation, and non-occupancy energy. The advantage is that information can be obtained accurately. In addition, an embodiment of the present invention, including the shield to block the effect of the high voltage applied to the electron gun, to prevent other electrons from entering the sample, and the signal output by the electron rather than the signal by the light emitted from the sample Has the effect of preventing.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be appreciated by those skilled in the art that various other modifications and variations can be made without departing from the spirit and scope of the invention, All fall within the scope of the appended claims.

1 is a perspective view of a conventional photodetector comprising a photoelectron multiplier,
2 is a cross-sectional view schematically showing the configuration of a photodetector having a microchannel plate according to an embodiment of the present invention;
3 is an enlarged partial cross-sectional view of a portion in which a window and a micro channel plate exist in FIG. 2 according to one embodiment of the present invention;
4 is a graph of transmittance of photon energy in a microchannel plate and a window in a photodetector according to an exemplary embodiment of the present invention;
5 is a flowchart illustrating a light detection method using a photodetector having a microchannel plate according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings. Throughout the specification, when a part is 'connected' to another part, this includes not only 'directly connected' but also 'indirectly connected' with another element in between. do. In addition, "including" a certain component does not exclude other components unless specifically stated otherwise, it means that may further include other components.

Hereinafter will be described the configuration of a photodetector having a micro-channel plate according to an embodiment of the present invention. First, Figure 2 shows a cross-sectional view showing the configuration of a photodetector having a micro-channel plate according to an embodiment of the present invention. 3 shows a partial cross-sectional view of the photodetector with respect to the portion where the micro channel plate 70 is located.

As shown in Figures 2 and 3, the photodetector having a micro-channel plate according to an embodiment of the present invention, the shield 110, the grid 50, the window 60, the voltage applying unit 80, the anode Layer 82, detection means 90 and analysis means 100. Such a photodetector is provided in the vacuum chamber 20. Therefore, photodetection by the photodetector is performed in a vacuum atmosphere.

The electron gun 30 scans the electron beam 31 with the sample 40. The sample 40 is irrespective of its kind as long as it emits light 2 by the electron beam 31 such as a metal or a semiconductor. In the sample 40 in which the electron beam 31 is scanned, light 2 having a specific photon energy is emitted. The photon energy of the light 2 emitted from the sample 40 corresponds to about 9.5 eV. The emitted light 2 is incident into the shield 110. Shield 110 is also provided in the form of a vacuum tube open on both sides. The shield 110 serves to block the effect of the high voltage on the electron gun 30 when a high voltage is applied to the microchannel plate 70 by the voltage applying unit 80 which will be described later. . In addition, other external electrons other than the electrons emitted from the sample 40 are prevented from being introduced, and signal output by the electrons other than the signal by the light 2 is prevented. The shield 110 is composed of a metal film, it is preferable that the shield is provided with a non-ferrous metal such as Ni-Mo alloy, Al and the like does not run magnetic.

And, the diameter of the shield 110 according to an embodiment of the present invention is composed of about 25 ~ 70 mm. Therefore, more light 2 can be incident than the photodetector using the photoelectron multiplier described in the prior art. Therefore, more signals can be output and the measurement time is about 1/10 of that of the photodetector using the photoelectron multipliers.

The photodetector according to the embodiment of the present invention may include a grid 50. When the light 2 emitted from the sample 40 is incident into the shield 110, it is transmitted through the grid 50. The grid 50 serves to prevent the window 60, which will be described later, from being charged to the anode or the cathode by adjusting the incident light 2.

As shown in FIGS. 2 and 3, the light 2 passing through the grid 50 is transmitted to the window 60. Window 60 according to an embodiment of the present invention is composed of SrF ₂ . Such SrF ₂ The window 60 is configured to about 1.5 ~ 2.5mm. As will be explained later, SrF ₂ The window 60 has a low transmittance as the photon energy increases. Therefore, it acts as a low pass filter.

The transmitted light transmitted through the window 60 is incident on the microchannel plate (MCP) 70. The microchannel plate 70 according to the embodiment of the present invention has a chevron pattern. When the transmitted light is incident on the micro channel plate 70, secondary electrons are emitted. 2 and 3, the microchannel plate 70 includes a coating layer 71 on one side of the direction in which the transmitted light is incident. The coating layer 71 serves to induce secondary electrons to be well emitted from the micro channel plate 70. The coating layer 71 is provided in about 2500 ~ 3500Å degree, the material is composed of KBr. The microchannel plate 70 has a higher transmittance as the photon energy increases. Therefore, it serves as a high pass filter.

3, a high voltage is applied to the micro channel plate 70 by the voltage applying unit 80. When a high voltage is applied to the micro channel plate 70, the emitted secondary electrons are accelerated. The voltage applying unit 80 according to the exemplary embodiment of the present invention includes an electrode layer connected to ground on each side of the micro channel plate 70 and an electrode layer through which high voltage flows by the voltage means 81. The voltage applied to the micro channel plate 70 by the voltage applying unit 80 is about 1500 to 2500V.

Secondary electrons accelerated by the voltage applied from the voltage applying unit 80 are amplified in the anode layer 82 and are emitted in the form of pulse waves. The detection means 90 is connected to the anode layer 82 to detect secondary electrons in the form of pulse waves. The analyzing means 100 connected to the detecting means 90 analyzes the secondary electrons in the form of pulse waves to detect the electronic state of the sample 40, the orbital of the sample 40, the electron occupancy state and energy of the sample 40, Information on the non-occupied state and energy of the sample 40 is obtained.

4 illustrates a graph of transmittances of the microchannel plate 70 and the window 60 according to photon energy in the photodetector having the microchannel plate 70 according to an embodiment of the present invention. As shown in FIG. 4, as the photon energy increases, the transmittance of the window 60 is lowered. In particular, it can be seen that while maintaining a high transmittance is continuously reduced. Thus, the window 60 serves as a low pass filter in the photodetector. On the other hand, the transmittance of the microchannel plate 70 increases with increasing photon energy. Thus, the micro channel plate 70 functions as a high pass filter. A portion shown by an oblique line in FIG. 4 corresponds to a photon energy using area A incident into the shield 110 used in one embodiment of the present invention.

Hereinafter will be described a light detection method using a photodetector having a micro-channel plate according to an embodiment of the present invention. The configuration of the photodetector used in the photodetection method is as described above. First, FIG. 5 is a flowchart illustrating a light detection method using a photodetector having a microchannel plate according to an embodiment of the present invention.

First, the electron beam 31 is scanned into the sample 40 by the electron gun 30 (S10). By adjusting the electron gun 30, it is possible to appropriately control the intensity of the electron beam 31 scanned by the sample 40. When the electron beam 31 is scanned into the sample 40, the light 2 having a specific photon energy is emitted from the sample 40 (S20). At this time, the intensity of the electron beam 31 may be adjusted such that the photon energy of the emitted light 2 is about 9.5 eV.

Then, the light 2 emitted from the sample 40 is incident to the grid 50 provided in the shield 110 (S30). At least one mirror may be placed and incident into the shield 110 to adjust the path of the light 2 emitted from the sample 40. As described above, the grid 50 is for preventing the SrF ₂ window 60 from being charged to the positive electrode or the negative electrode. The light 2 passing through the grid 50 is transmitted to the window 60 made of SrF ₂ material (S40).

The transmitted light transmitted through the window 60 is incident on the micro channel plate 70 (S50). When the transmitted light is incident on the micro channel plate 70, the secondary tank is emitted (S60). As described above, the micro channel plate 70 includes a chevron pattern, and the micro channel plate 70 is provided with a coating layer 71 composed of SrF ₂ to induce secondary electron emission. Then, the voltage is applied to the micro channel plate 70 by the voltage applying unit 80 connected to the micro channel plate 70 (S70). The applied voltage is about 1500 to 2500V. When the high voltage is applied, the emitted secondary electrons are accelerated (S70).

The accelerated secondary tank is amplified by the anode layer 82 to emit secondary electrons in the form of pulse waves (S80). According to the light detection method according to the present invention, the secondary electrons are emitted in the form of pulse waves. Then, the secondary electrons in the form of pulse wave emitted from the detection means 90 connected to the anode layer 82 is detected (S90), and the analysis means 100 connected to the detection means 90 is formed in such a pulse wave form. The secondary electrons are analyzed to obtain information about the electronic state of the sample 40, the orbital of the sample 40, the electron occupancy state and energy of the sample 40, the non-occupied state and energy of the sample 40, and the like. (S100).

1: Conventional photodetector
2: light
3: single lens window
4: KCl thin film
5: Photo Electron Multiplier
6: dynode
7: optoelectronic
8: electrode
9: collector
10: amplifier
11: pulse counter circuit
20: vacuum chamber
30: electron gun
31: electron beam
40: Sample
50: grid
60: window
70: microchannel board
71: coating layer
80: voltage application part
81: voltage means
82: anode layer
90: detection means
100: analysis means
110: Shield

Claims

In the photodetector for detecting the light emitted from the sample by scanning the electron beam with the electron gun,
A window composed of SrF ₂ through which the light emitted from the sample is transmitted to emit transmitted light;
A micro channel plate to which the transmitted light emitted from the window is incident to emit pulsed secondary electrons;
Detection means for detecting the secondary electrons in the form of pulses emitted from the microchannel plate; And
And a coating layer provided on one side of the microchannel plate on which the transmitted light is incident to induce emission of secondary electrons.
The thickness of the coating layer is 2500 ~ 3500Å, the coating layer is a photodetector having a micro-channel plate, characterized in that consisting of KBr.

The method of claim 1,
And a voltage applying unit for accelerating the secondary electrons by applying a voltage to the micro channel plate.

The method of claim 2,
And a voltage applied to the microchannel plate by the voltage applying unit is 1700 to 2500V.

delete

The method of claim 1,
The micro-channel plate is a photodetector having a micro-channel plate, characterized in that provided with a chevron pattern.

The method of claim 7, wherein
The photodetector having a micro channel plate, characterized in that the thickness of the window is 1.5 ~ 2.5mm.

The method of claim 1,
And a shield having the window and the micro channel plate therein in the form of a hollow tube.

The method of claim 9,
The material of the shield is made of a non-ferrous metal, the thickness of the shield is a photodetector having a micro-channel plate, characterized in that 0.5 ~ 2 mm.

The method of claim 1,
And a grid provided to be spaced apart from one side of the window from which the light is scanned at a predetermined interval so as to control the light to be scanned such that the window does not become an anode or a cathode.

The method of claim 2,
And a bipolar plate connected to the detection means and configured to amplify the secondary electrons accelerated by the voltage applied by the voltage applying unit to converge and discharge the secondary electrons in the form of a pulse wave. Photodetectors with plates.

In the sample analysis system using the photodetector of any one of Claims 1, 2, 3, 7, 8, 9, 10, 11 or 12,
And an analysis means connected to the detection means included in the photodetector for analyzing the sample information by receiving secondary electrons in the form of pulse waves detected by the detection means. Sample Analysis System.

The method of claim 13,
The analyzing means analyzes the secondary electrons to obtain at least one of the electronic state of the sample, the orbital state of the sample, the electron occupancy state of the sample and the non-electron occupancy state of the sample. Sample analysis system using a photodetector having.

In the photodetection method using the photodetector of any one of Claims 1, 2, 3, 7, 8, 9, 10, 11 or 12,
Scanning the electron beam by the electron gun onto the sample to emit light having a particular photon energy in the sample;
Transmitting the emitted light through a window composed of SrF ₂ to emit transmitted light;
The transmitted light is incident on the microchannel plate to emit pulsed secondary electrons; And
Detecting the secondary electrons by a detection means;
The secondary electron emission step,
And inducing the emission of the secondary electrons by a coating layer composed of KBr provided on one side of the microchannel plate.

The method of claim 15,
The secondary electron emission step,
And accelerating the secondary electrons by applying a voltage to the microchannel plate by a voltage applying unit.

delete

The method of claim 15,
Before the transmitted light emitting step,
And adjusting the light such that the window does not become an anode or a cathode by a grid provided at a predetermined interval on one side of the window from which the light is scanned. Photodetection method using a detector.

17. The method of claim 16,
The method further includes the step of amplifying the secondary electrons accelerated by a voltage applied by the voltage applying unit to the positive electrode plate to transmit the secondary electrons in the form of pulse waves to the detection means. Photodetection method using photodetector.

In the sample analysis method using the photodetector of any one of Claims 1, 2, 3, 7, 8, 9, 10 or 11.
Scanning the electron beam by the electron gun onto the sample to emit light having a particular photon energy in the sample;
Transmitting the emitted light through a window composed of SrF ₂ to emit transmitted light;
Inducing emission of the secondary electrons by a coating layer composed of KBr provided on one side of a micro channel plate, and transmitting the incident light to the micro channel plate to emit secondary electrons in the form of pulse waves;
Detecting the secondary electrons by detection means; And
And analyzing the detected pulse waveforms by analyzing means connected to the detecting means to obtain information about a sample.