CN101325093B - Minisize nuclear battery manufacture method - Google Patents

Abstract

The invention discloses a minitype nuclear battery, which mainly solves the problem that the nuclear battery manufacturing is easier than the SiC technology realization. A low doping epitaxial layer (2) and an ohmic contact electrode (3) are respectively arranged at the upper part and the lower part of an N-type high doping SiC substrate (1), wherein, a circular schottky contact layer (4) is deposited on the upper surface of the low doping epitaxial layer (2), and a SiO2 passivating layer (5) and a bonding layer (7) are arranged on the circumference at the outer edge of the schottky contact layer. The schottky contact layer (4) and a schottky contact electrode (6) are formed by adopting an identical technology, that is, a schottky contact hole is etched by adopting wet process in the center position of the SiO2 passivating layer (5), and Ni, Pt or Au with the thickness being 5 to 20 nm deposited on the SiO2 passivating layer on the hole or at the periphery of the hole, and the schottky contact layer (4) and the schottky contact electrode (6) are respectively formed after the SiO2 passivating layer is peeled off. The minitype nuclear battery has the advantages of simple technology and high conversion efficiency, and is applicable in directly converting the nuclear energy radiated by isotopes into the electric energy.

Description

The minisize nuclear battery method for making

Technical field

The invention belongs to microelectronics technology.Relate to semiconductor diode, particularly minisize nuclear battery can be used for the nuclear energy of isotope radiation directly is converted to electric energy.

Background technology

Minisize nuclear battery be a kind of employing semiconductor diode as energy converting structure, nuclear energy directly is converted to the device of electric energy.It utilizes radioactive isotope, as ⁶³Ni, ¹⁴⁷The ionisation effect of Pm radiation emitted particle in semiconductor material collected the electron hole pair formation electric current that radiating particle produces as the energy in semiconductor, produce output power.Minisize nuclear battery can be used as the power source of various storeies and MEMS system, and the long-life under the extreme case such as space flight, the portable power source of long-term work Maintenance free.The IV characteristic of semiconductor diode radiation voltaic element can be expressed as follows:

$I=I_S[\exp \left(\frac{\mathrm{qV}}{\mathrm{nkT}}\right)-1]-I_L$

Is is a leakage current, I _LBe the electric current that is produced by radiating particle, A is a device area, and n is an ideal factor.

Open-circuit voltage V _OCWith short-circuit current I _SCRelation can be expressed as follows:

$V_{\mathrm{OC}}=\frac{\mathrm{nkT}}{q}\ln \left(\frac{I_{\mathrm{SC}}}{I_S}\right),$ I wherein _SC=I _L.

Peak power output P _Out=FFV _OCI _SC, wherein FF is a fill factor, curve factor.

According to above theory,, must have a lower leakage current as the semiconductor diode of energy converting structure if want to possess high output power.

As Fig. 1, document " Final Scientific/Technical Report (US.Department of Energy Award No.DE-FG07-99ID13781) " A NuclearMicrobattery for MEMS Devices " " and " Hang Guo; and Amit LalNANOPOWER BETAVOLTAIC MICROBATTERIES The 12th InternationalConference on Solid State Sensors; Actuators and Microsystems; Boston; June 8-12,2003 " have introduced and have adopted the minisize nuclear battery of silicon PN junction as energy converting structure.Such battery adopts low-energy electron to produce the ionizing radiation effect in semiconductor material, generates irradiation and gives birth to electron hole pair, and near the living charge carrier of irradiation in depletion region and the depletion region in minority diffusion length scope can be collected the generation output power.The minisize nuclear battery mature preparation process of this silicon, with low cost, and can make the contact area that as shown in fig. 1 inverted triangle surface structure increases device and radiation source.But silicon materials are owing to the little characteristic of its energy gap, and the PN junction leakage current of making is bigger, make lower with the energy content of battery conversion efficiency of its preparation.And silicon materials can't be applicable to high temperature intense radiation environment, and under higher working temperature, the leakage current of silicon PN junction can sharply rise, make battery lose output power, and the intense radiation meeting forms a large amount of defectives in silicon materials, causes minority carrier life time to descend, and leakage current increases.

Silit is as third generation semiconductor, temperature characterisitic that it is superior and radiation-resisting performance not only can satisfy the requirement of the prolonged application under extreme environments such as high temperature intense radiation, and because its energy gap is big, leakage current with its diode of making is very low, can obtain open-circuit voltage and the energy conversion efficiency higher, become current up-and-coming irradiation battery applications material than silica-based micronucleus battery.Reported at present the research of silit PN and PiN knot irradiation battery in the world, see document " 4H SiCbeta-powered temperature transducer IEEE SENSORS 2007 Conference942-945 ", " Demonstration of a 4H SiC betavoltaic cell APPLIEDPHYSICS LETTERS 88; 033506_2006_ ", " 4H SiC betavoltaicpowered temperature transducer APPLIED PHYSICS LETTERS 91; 053,511 2007 ", " Demonstration of a radiation resistant; highefficiency SiC betavoltaic APPLIED PHYSICS LETTERS 88,0641012006 ".

The SiC material is owing to its hardness height, and characteristics such as epitaxial growth difficulty make processes relatively more difficult.When preparation SiC PN junction, generally be to adopt the low-doped n type layer of homoepitaxy technology growth, and then adopt homoepitaxy or particle implantttion technique at the highly doped p type layer of surface preparation skim, as shown in Figure 2.All there are certain defective in this silit PN and PiN knot irradiation battery on technology and structure.Because SiC technology is not very perfect at present, if often doping content is not high for the P type layer of the preparation of employing homoepitaxy, causes built-in potential barrier lower, and bring difficulty for the preparation of p type Ohmic contact; If the method that adopts ion to inject forms p type layer, except the technological process more complicated, and can cause surface damage to the activated at process of implanted dopant, strengthen the surface recombination effect, the leakage current of device is increased, influence battery behavior.Structurally have only the living charge carrier of irradiation that depletion region is interior and a near minority diffusion length is interior to be collected, as the dotted portion among Fig. 2.In this PN junction structure, in order to prevent that Ohm contact electrode from stopping incident particle, Ohmic electrode must be made in a jiao of device, this can cause from Ohmic electrode irradiation far away and give birth in the process that charge carrier transporting by the defective on surface is compound, and incident particle must pass the SiO2 passivation layer and the part P type layer on surface, be commonly called as dead layer, cause energy loss, reduce energy conversion efficiency.

Summary of the invention

The objective of the invention is to avoid the difficult problem that realizes of above-mentioned SiC PN junction technology, and the thick problem of surperficial dead layer, the minisize nuclear battery that a kind of technology is easy to realize has been proposed, to reduce surperficial dead layer thickness, improve energy conversion efficiency.

For achieving the above object, minisize nuclear battery structure provided by the invention is to be respectively equipped with low-doped epitaxial loayer and Ohm contact electrode up and down at the highly doped SiC substrate of N type, wherein, the circular schottky contact layer of the top deposit of low-doped epitaxial loayer, the outward flange circumference of this schottky contact layer is provided with SiO ₂Passivation layer and bonded layer.

Described SiO ₂Be provided with the schottky junctions touched electrode between passivation layer and the bonded layer, this schottky contact layer and schottky junctions touched electrode are high barrier schottky metal Ni or Pt or the Au that thickness is less than or equal to 20nm.

The present invention is according to selecting different high barrier metals as schottky metal layer, following three kinds of processes of the preparation minisize nuclear battery of proposition.

Process 1:

On the highly doped SiC substrate of N type, utilize the low-doped epitaxial loayer of low pressure hot wall chemical vapor deposition method extension

The sample of externally delaying is carrying out 1100 ± 50 ℃ of following dry-oxygen oxidations, forms SiO ₂Passivation layer;

Utilize the back-etching 0.5 μ m of reactive ion etching method to the highly doped SiC substrate of N type;

The highly doped SiC substrate back of N type after etching adopts electron beam evaporation Ni metal, and the formation Ohmic contact of annealing in nitrogen atmosphere under 1000 ± 50 ℃;

At SiO ₂The centre position of passivation layer adopts wet etching to go out the Schottky contacts window, and reaches the SiO of window periphery on this window ₂The Ni of deposition thickness 5～20nm on the passivation layer peels off and forms schottky metal layer and Schottky electrode respectively;

Deposited by electron beam evaporation Cr/Au forms bonded layer on Schottky electrode.

Process 2:

On the highly doped SiC substrate of N type, utilize the low-doped epitaxial loayer of low pressure hot wall chemical vapor deposition method extension;

The sample of externally delaying is carrying out 1100 ± 50 ℃ of following dry-oxygen oxidations, forms SiO ₂Passivation layer;

Utilize the back-etching 0.5 μ m of reactive ion etching method to the highly doped SiC substrate of N type;

The highly doped SiC substrate back of N type after etching adopts electron beam evaporation Ni metal, and the formation Ohmic contact of annealing in nitrogen atmosphere under 1000 ± 50 ℃;

At SiO ₂The centre position of passivation layer adopts wet etching to go out the Schottky contacts window, and reaches the SiO of window periphery on this window ₂The Pt of deposition thickness 4～19nm on the passivation layer peels off and forms schottky metal layer and Schottky electrode respectively;

Deposited by electron beam evaporation Au forms bonded layer on Schottky electrode.

Process 3;

On the highly doped SiC substrate of N type, utilize the low-doped epitaxial loayer of low pressure hot wall chemical vapor deposition method extension;

The sample of externally delaying is carrying out 1100 ± 50 ℃ of following dry-oxygen oxidations, forms SiO ₂Passivation layer;

Utilize the back-etching 0.5 μ m of reactive ion etching method to the highly doped SiC substrate of N type;

The highly doped SiC substrate back of N type after etching adopts electron beam evaporation Ni metal, and the formation Ohmic contact of annealing in nitrogen atmosphere under 1000 ± 50 ℃;

At SiO ₂The centre position of passivation layer adopts wet etching to go out the Schottky contacts window, and reaches the SiO of window periphery on this window ₂The Au of deposition thickness 6～20nm on the passivation layer peels off and forms schottky metal layer and Schottky electrode respectively;

Deposited by electron beam evaporation Au forms bonded layer on Schottky electrode.

The present invention is owing to adopt schottky junction to substitute the energy conversion component of PN junction as the irradiation battery, and the technology that makes is simple, is easy to realize; Simultaneously owing to adopt translucent schottky metal layer, can effectively reduce metal electrode to the stopping of low energy particle, improve energy conversion efficiency; In addition, owing to adopt the schottky metal of high potential barrier, improved the open-circuit voltage of minisize nuclear battery.

Test result shows, adopts the minisize nuclear battery of Ni/Cr/Au 200/50/200 as schottky metal layer, energy conversion efficiency about 3%.

Description of drawings

Fig. 1 is existing Si PN junction minisize nuclear battery synoptic diagram;

Fig. 2 be existing SiC PN junction the minisize nuclear battery synoptic diagram;

Fig. 3 is a minisize nuclear battery structural representation of the present invention;

Fig. 4 method for making schematic flow sheet of the present invention;

Fig. 5 is to the electric performance test of common SiC schottky junction minisize nuclear battery figure as a result.

Embodiment

With reference to Fig. 3, minisize nuclear battery of the present invention adopts the highly doped SiC substrate 1 of N type, it above the substrate the low-doped epitaxial loayer 2 of one deck n type, it below the substrate Ohm contact electrode 3, the circular schottky contact layer 4 of the top deposit of the low-doped epitaxial loayer 2 of n type, the outward flange circumference of schottky contact layer is provided with SiO ₂Passivation layer 5, this SiO ₂Be followed successively by schottky junctions touched electrode 6 and bonded layer 7 above the passivation layer.This schottky contact layer 4 and schottky junctions touched electrode 6 are high barrier schottky metal Ni or Pt or the Au that thickness is less than or equal to 20nm, and this bonded layer adopts Ci/Au or Au.

With reference to Fig. 4, method for making of the present invention illustrates by following examples.

Embodiment 1

Step 1. is the low-doped epitaxial loayer of extension on the SiC substrate, as Fig. 4 a.

Select for use the highly doped 4H-SiC substrate of N type as substrate 1, after the cleaning, adopting low pressure hot wall chemical vapor deposition method growth thickness on its epitaxial surface is the low-doped epitaxial loayer 2 of 4H-SiC of 10 μ m.Epitaxial growth temperature is 1570 ℃, and pressure is 100mbar; Reacting gas is silane, propane; Carrier gas is a pure hydrogen.

Step 2. forms SiO on epitaxial loayer ₂Passivation layer is as Fig. 4 b.

The sample of externally delaying carries out 2 hours dry-oxygen oxidation under 1100 ± 50 ℃ of temperature, form the passivation protection layer of thickness 25 ± 3nm);

Step 3. prepares Ohmic contact at substrate back, as Fig. 4 c.

3.1 utilizing the reactive ion etching method is the thick SiC layer of 0.5 μ m in the back-etching degree of depth of the highly doped SiC substrate 1 of N type;

3.2 the highly doped SiC substrate of the N type after etching 1 back side adopts electron beam evaporation thickness to be at least the Ni metal level of 200nm;

3.3 device temperature is set to 1000 ± 50 ℃, annealing formed Ohmic contact 3 in 2 minutes in nitrogen atmosphere;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Ni of deposition thickness 5nm on the passivation layer,

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5. is made bonded layer on Schottky electrode, as Fig. 4 e.

First deposited by electron beam evaporation Cr/Au 10/200nm on Schottky electrode 6 peels off by ultrasound wave and forms bonded layer 7.

Embodiment 2

Step 1～3 are identical with embodiment 1;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Ni of deposition thickness 20nm on the passivation layer,

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5 is identical with embodiment 1.

Embodiment 3

Step 1～3 are identical with embodiment 1;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Ni of deposition thickness 12nm on the passivation layer,

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5 is identical with embodiment 1.

Embodiment 4

Step 1. is the low-doped epitaxial loayer of extension on the SiC substrate, as Fig. 4 a.

Select for use the highly doped 4H-SiC substrate of N type as substrate 1, after the cleaning, adopting low pressure hot wall chemical vapor deposition method growth thickness on its epitaxial surface is the low-doped epitaxial loayer 2 of 4H-S iC of 10 μ m.Epitaxial growth temperature is 1570 ℃, and pressure is 100mbar; Reacting gas is silane, propane; Carrier gas is a pure hydrogen.

Step 2. forms SiO on epitaxial loayer ₂Passivation layer is as Fig. 4 b.

The sample of externally delaying carries out 2 hours dry-oxygen oxidation under 1100 ± 50 ℃ of temperature, form the passivation protection layer of thickness 25 ± 3nm);

Step 3. prepares Ohmic contact at substrate back, as Fig. 4 c.

3.1 utilizing the reactive ion etching method is the thick SiC layer of 0.5 μ m in the back-etching degree of depth of the highly doped SiC substrate 1 of N type;

3.2 the highly doped SiC substrate of the N type after etching 1 back side adopts electron beam evaporation thickness to be at least the Ni metal level of 200nm;

3.3 device temperature is set to 1000 ± 50 ℃, annealing formed Ohmic contact 3 in 2 minutes in nitrogen atmosphere;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Pt of deposition thickness 4nm on the passivation layer;

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5. is made bonded layer on Schottky electrode, as Fig. 4 e.

First deposited by electron beam evaporation Au 200nm on Schottky electrode 6 peels off with ultrasound wave and forms bonded layer 7.

Embodiment 5

Step 1～3 are identical with embodiment 4;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Pt of deposition thickness 19nm on the passivation layer;

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5 is identical with embodiment 4.

Embodiment 6

Step 1～3 are identical with embodiment 4;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Pt of deposition thickness 10nm on the passivation layer;

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5 is identical with embodiment 4.

Embodiment 7

Step 1. is the low-doped epitaxial loayer of extension on the SiC substrate, as Fig. 4 a.

Select for use the highly doped 4H-SiC substrate of N type as substrate 1, after the cleaning, adopting low pressure hot wall chemical vapor deposition method growth thickness on its epitaxial surface is the low-doped epitaxial loayer 2 of 4H-SiC of 10 μ m.Epitaxial growth temperature is 1570 ℃, and pressure is 100mbar; Reacting gas is silane, propane; Carrier gas is a pure hydrogen.

Step 2. forms SiO on epitaxial loayer ₂Passivation layer is as Fig. 4 b.

The sample of externally delaying carries out 2 hours dry-oxygen oxidation under 1100 ± 50 ℃ of temperature, form the passivation protection layer of thickness 25 ± 3nm);

Step 3. prepares Ohmic contact at substrate back, as Fig. 4 c.

3.1 utilizing the reactive ion etching method is the thick SiC layer of 0.5 μ m in the back-etching degree of depth of the highly doped SiC substrate 1 of N type;

3.2 the highly doped SiC substrate of the N type after etching 1 back side adopts electron beam evaporation thickness to be at least the Ni metal level of 200nm;

3.3 device temperature is set to 1000 ± 50 ℃, annealing formed Ohmic contact 3 in 2 minutes in nitrogen atmosphere;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Au of deposition thickness 6nm on the passivation layer;

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5. is made bonded layer on Schottky electrode, as Fig. 4 e.

First deposited by electron beam evaporation Au 200nm on Schottky electrode 6 peels off with ultrasound wave and forms bonded layer 7.

Embodiment 8

Step 1～3 are identical with embodiment 7;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre position of passivation layer 5 erodes away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Au of deposition thickness 20nm on the passivation layer;

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5 is identical with embodiment 7.

Embodiment 9

Step 1～3 are identical with embodiment 7;

Step 4. deposit schottky contact layer and Schottky electrode are as Fig. 4 d.

4.1 adopting concentration is 5% buffered HF acid corrosion 10 seconds, at SiO ₂The centre of passivation layer 5 is put and is eroded away the Schottky contacts window;

4.2 on the window that erodes away, reach the SiO of window periphery ₂The Au of deposition thickness 12nm on the passivation layer;

4.3 peel off formation schottky metal layer 4 on described window respectively by ultrasound wave, at the SiO of described window periphery ₂Form Schottky electrode 6 on the passivation layer;

Step 5 is identical with embodiment 7.

Effect of the present invention can be by further specifying common SiC schottky junction device detection result.

Adopt common Schottky contacts in the test, promptly metal level is Ni/Cr/Au, and thickness is respectively 200/50/200nm, is 1 * 2cm at area ², activity is 10mCi, under the laminar rectangle irradiation bomb apart from the about 3mm of Schottky electrode, to the energy converting structure of SiC schottky junction as minisize nuclear battery, carries out its feasibility checking.

Test result is: the open-circuit voltage of the single tube of battery is 0.5v, and short-circuit current is 39.4nA/cm ²The single tube peak power output is 6.38nW/cm ², fill factor, curve factor is 0.31.Its conversion efficiency about 3%.Test result as shown in Figure 5.Can predict, be the schottky metal layer structure of 5～20nm if adopt thickness of the present invention, and its energy conversion efficiency has bigger raising potentiality.

Claims (3)

1. method of making minisize nuclear battery comprises following process:

On the highly doped SiC substrate of N type (1), utilize the low-doped epitaxial loayer of low pressure hot wall chemical vapor deposition method extension (2);

The sample of externally delaying carries out dry-oxygen oxidation under 1100 ± 50 ℃, form SiO ₂Passivation layer (5);

Utilize the back-etching 0.5 μ m of reactive ion etching method to the highly doped SiC substrate of N type;

The highly doped SiC substrate back of N type after etching adopts electron beam evaporation Ni metal, and the formation Ohmic contact (3) of annealing in nitrogen atmosphere under 1000 ± 50 ℃;

At SiO ₂The centre position of passivation layer (5) adopts wet etching to go out the Schottky contacts window, and reaches the SiO of window periphery on this window ₂Deposition thickness is the Ni of 5～20nm on the passivation layer, peels off and forms schottky contact layer (4) and Schottky electrode (6) respectively;

Go up deposited by electron beam evaporation Cr/Au at Schottky electrode (6), form bonded layer (7).

2. method of making minisize nuclear battery comprises following process:

On the highly doped SiC substrate of N type (1), utilize the low-doped epitaxial loayer of low pressure hot wall chemical vapor deposition method extension (2);

The sample of externally delaying carries out dry-oxygen oxidation under 1100 ± 50 ℃, form SiO ₂Passivation layer (5);

Utilize the back-etching 0.5 μ m of reactive ion etching method to the highly doped SiC substrate of N type;

The highly doped SiC substrate back of N type after etching adopts electron beam evaporation Ni metal, and the formation Ohmic contact (3) of annealing in nitrogen atmosphere under 1000 ± 50 ℃;

At SiO ₂The centre position of passivation layer (5) adopts wet etching to go out the Schottky contacts window, and reaches the SiO of window periphery on this window ₂The Pt of deposition thickness 4～19nm on the passivation layer peels off and forms schottky contact layer (4) and Schottky electrode (6) respectively;

Go up deposited by electron beam evaporation Au at Schottky electrode (6) and form bonded layer (7).

3. method of making minisize nuclear battery comprises following process:

On the highly doped SiC substrate of N type (1), utilize the low-doped epitaxial loayer of low pressure hot wall chemical vapor deposition method extension (2);

The sample of externally delaying carries out dry-oxygen oxidation under 1100 ± 50 ℃, form SiO ₂Passivation layer (5);

Utilize the back-etching 0.5 μ m of reactive ion etching method to the highly doped SiC substrate of N type;

The highly doped SiC substrate back of N type after etching adopts electron beam evaporation Ni metal, and the formation Ohmic contact (3) of annealing in nitrogen atmosphere under 1000 ± 50 ℃;

At SiO ₂The centre position of passivation layer (5) adopts wet etching to go out the Schottky contacts window, and reaches the SiO of window periphery on this window ₂The Au of deposition thickness 6～20nm on the passivation layer peels off and forms schottky contact layer (4) and Schottky electrode (6) respectively;

Go up deposited by electron beam evaporation Au at Schottky electrode (6) and form bonded layer (7).

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