CN117832081A - Inclined plane terminal PIN diode with introduced surface positive charges and preparation method thereof - Google Patents
Inclined plane terminal PIN diode with introduced surface positive charges and preparation method thereof Download PDFInfo
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- CN117832081A CN117832081A CN202311825529.2A CN202311825529A CN117832081A CN 117832081 A CN117832081 A CN 117832081A CN 202311825529 A CN202311825529 A CN 202311825529A CN 117832081 A CN117832081 A CN 117832081A
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- pin diode
- silicon dioxide
- aluminum metal
- positive charge
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- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 238000000137 annealing Methods 0.000 claims abstract description 16
- 230000005684 electric field Effects 0.000 claims abstract description 15
- 238000000034 method Methods 0.000 claims abstract description 12
- 230000005855 radiation Effects 0.000 claims abstract description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 68
- 235000012239 silicon dioxide Nutrition 0.000 claims description 34
- 239000000377 silicon dioxide Substances 0.000 claims description 34
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 22
- 239000000758 substrate Substances 0.000 claims description 18
- 238000000151 deposition Methods 0.000 claims description 17
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 17
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000005530 etching Methods 0.000 claims description 3
- 238000009279 wet oxidation reaction Methods 0.000 claims description 3
- 230000000903 blocking effect Effects 0.000 abstract description 7
- 230000015556 catabolic process Effects 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000002285 radioactive effect Effects 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
According to the inclined plane terminal PIN diode with the introduced surface positive charges and the preparation method thereof, the interface positive charges are introduced into the inclined plane terminal structure PIN diode by adopting a method of annealing and overlapping high electric fields or total dose radiation. The device plays a role in expanding a depletion region similar to a slope JTE when in reverse operation, so that the blocking voltage of the device is improved under the condition of not changing the structure of the device.
Description
Technical Field
The invention belongs to the technical field of semiconductor devices, and particularly relates to a bevel terminal PIN diode with surface positive charges introduced and a preparation method thereof.
Background
In the large environment where the power electronics industry is wholly oriented, power semiconductor devices that play a decisive role in power electronics are direct factors that affect the cost and efficiency of power electronics equipment. Although Silicon-based power devices are mature at present, as power semiconductors gradually develop to high power, high frequency and low power consumption, silicon (Si) -based devices are limited by their own physical characteristics, and are difficult to be applied to some high-voltage, high-temperature, high-efficiency and high-power density application scenarios.
Silicon carbide (SiC) materials are coming to get attention of practitioners because of their superior physical properties, and compared with silicon-based devices, the characteristics of high thermal conductivity, large forbidden bandwidth, and the like of the silicon carbide materials determine the application scenarios of the silicon carbide materials in high current density, high breakdown field strength, and high operating temperature. Compared with Si diodes under the same level, the characteristic on-resistance and the switching loss of the SiC diode are used for higher working frequency, and the high-temperature stability is greatly improved by the high thermal conductivity.
In the case of a vertical SiC PIN diode, in the blocking state, the boundary thereof may generate an electric field concentration phenomenon due to a non-ideal boundary effect, resulting in early breakdown of the device under the condition of a lower blocking voltage than designed. For bevel vertical devices, the peak electric field cannot be introduced inside the device, and there is a limit to high frequency applications. At the same time, these termination structures require a large boundary area, increasing manufacturing costs.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a bevel termination PIN diode with positive charges introduced on the surface and a preparation method thereof. The technical problems to be solved by the invention are realized by the following technical scheme:
in a first aspect, the present invention provides a method for preparing a bevel termination PIN diode with a positive surface charge, comprising:
s100, obtaining an N-type substrate;
s200, epitaxially growing an N-epitaxial layer on the surface of the N-type substrate;
s300, epitaxially growing a P region epitaxial layer on the N-epitaxial layer; the N-epitaxial layer and the N-type substrate form a trapezoid table top;
s400, forming a silicon dioxide layer on the trapezoid table top so that the silicon dioxide layer covers the trapezoid table top and the N-type substrate, and performing annealing treatment;
s500, depositing aluminum metal on the silicon dioxide layer, and placing the device obtained by depositing the aluminum metal in a radiation environment to introduce additional positive charges at the interface of silicon dioxide and silicon carbide;
and S600, cleaning aluminum metal on the surface of the silicon dioxide, and etching an opening to form ohmic contact to obtain the inclined plane terminal PIN diode with the surface positive charges introduced.
Optionally, the N-type substrate is a SiC substrate with the thickness of 360 μm and the doping concentration of 5e18cm -3 -1e20cm -3 。
Optionally, the doping concentration of the N-epitaxial layer is 1e14cm -3 ～1e16cm -3 。
Optionally, the doping concentration of the P region epitaxial layer is 1e16cm -3 ～5e19cm -3 。
Optionally, the thickness of the silicon dioxide layer is 0.5-2 μm.
Alternatively, the silicon dioxide layer is formed by means of deposition of an oxide layer or wet oxidation.
Optionally, the annealing treatment in S400 is NO annealing, where the annealing temperature is above 1200 degrees celsius and the time is greater than 30 minutes.
Optionally, S500 includes:
aluminum metal is deposited on the silicon dioxide layer, and the device obtained by depositing the aluminum metal is placed in a high forward electric field environment with an electric field strength higher than 7MV/cm so as to introduce additional positive charges at the interface between silicon dioxide and silicon carbide.
Optionally, S500 includes:
aluminum metal is deposited on the silicon dioxide layer, and the device obtained by depositing the aluminum metal is placed in a low-pressure biased total dose radiation environment for at least more than 10 minutes so as to introduce additional positive charges at the interface of silicon dioxide and silicon carbide.
In a second aspect, the invention provides a surface positive charge-introducing inclined plane terminal PIN diode prepared by the preparation method of the surface positive charge-introducing inclined plane terminal PIN diode.
The beneficial effects are that:
according to the inclined plane terminal PIN diode with the introduced surface positive charges and the preparation method thereof, the interface positive charges are introduced into the inclined plane terminal structure PIN diode by adopting a method of annealing and overlapping high electric fields or total dose radiation. The device plays a role in expanding a depletion region similar to a slope JTE when in reverse operation, so that the blocking voltage of the device is improved under the condition of not changing the structure of the device.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
FIG. 1 is a prior art field plate structure termination diode, field limiting ring structure termination diode, and junction termination extension structure termination diode;
FIG. 2 is a schematic cross-sectional view of a device incorporating a surface positive charge in a bevel termination PIN diode provided by the invention;
FIG. 3 is a schematic diagram of three epitaxial and oxide layer deposition anneals in the method for preparing a bevel termination PIN diode with introduced positive surface charges provided by the invention;
FIG. 4 is a schematic illustration of the deposition and high electric field or total dose action of an aluminum electrode provided by the present invention;
fig. 5 is a schematic diagram of ohmic contact formation provided by the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto.
Before the present invention is described, the technical concept of the present invention will be briefly described.
In order to suppress premature breakdown of the prior art device below the designed blocking voltage. For bevel vertical devices, the peak electric field cannot be introduced inside the device, and there is a limit to high frequency applications. Meanwhile, the terminal structures need larger boundary area, the manufacturing cost is increased, and the boundary optimization of the device boundary through the boundary terminal technology is a reliable means. The invention provides a technology of a bevel terminal introducing positive charges, which introduces additional positive charges on a silicon dioxide bevel terminal by annealing and total dose irradiation, so as to improve the breakdown voltage of a device.
The following describes in detail the process of the preparation method of the inclined plane terminal PIN diode introducing positive surface charges.
Referring to fig. 2 to 5, the present invention provides a method for preparing a bevel termination PIN diode introducing positive surface charges, comprising:
s100, obtaining an N-type substrate 5;
s200, epitaxially growing an N-epitaxial layer 4 on the surface of the N-type substrate 5;
s300, epitaxially growing a P region epitaxial layer 3 on the N-epitaxial layer 4; the N-epitaxial layer 4 and the N-type substrate 5 form a trapezoid table top;
s400, forming a silicon dioxide layer 2 on the trapezoid table top so that the silicon dioxide layer 2 covers the trapezoid table top and the N-type substrate 5, and performing annealing treatment;
s500, depositing aluminum metal on the silicon dioxide layer 2, and placing the device obtained by depositing aluminum metal in a radiation environment to introduce additional positive charges at the interface between silicon dioxide and silicon carbide;
the invention can deposit aluminum metal on the silicon dioxide layer, and the device obtained by depositing aluminum metal is placed in a high forward electric field environment with the electric field intensity higher than 7MV/cm so as to introduce additional positive charges at the interface of silicon dioxide and silicon carbide. Or, depositing aluminum metal on the silicon dioxide layer, and placing the device obtained by depositing the aluminum metal in a low-pressure bias radiation environment for at least more than 10min so as to introduce additional positive charges at the interface of silicon dioxide and silicon carbide.
Noteworthy are: the total dose environment refers to the radioactive environment and the total dose refers to the amount of radiation received by the article. High energy rays are present in the radioactive environment to induce ionization effects in the device, thereby introducing electrons and holes.
After positive charges are introduced, the depletion region can be expanded when the device works reversely. The depletion region is expanded from the pn junction to the inclined plane, the curvature of the depletion region on the surface is reduced, the concentration difference is reduced, and the surface electric field concentration effect is relieved, so that the surface electric field is reduced, and the blocking voltage of the device is improved.
And S600, cleaning aluminum metal on the surface of the silicon dioxide, and etching an opening to form ohmic contact 1 to obtain the inclined plane terminal PIN diode with the surface positive charges introduced.
Wherein the N-type substrate is a SiC substrate, the thickness is 360 mu m, and the doping concentration is 1e19cm -3 -1e20cm -3 . The doping concentration of the N-epitaxial layer is 6e15cm -3 ～1e16cm -3 . The doping concentration of the P region epitaxial layer is 1e16cm -3 ～5e19cm -3 . The thickness of the silicon dioxide layer is 0.5-2 mu m. The silicon dioxide layer is formed by means of deposition of an oxide layer or wet oxidation. The annealing treatment mode is NO annealing, the annealing temperature is above 1200 ℃ and the time is more than 30min.
In a second aspect, referring to fig. 5, the present invention provides a surface positive charge-introducing slope termination PIN diode prepared by the preparation method of the surface positive charge-introducing slope termination PIN diode of the first aspect.
According to the inclined plane terminal PIN diode with the introduced surface positive charges and the preparation method thereof, the interface positive charges are introduced into the inclined plane terminal structure PIN diode by adopting a method of annealing and overlapping high electric fields or total dose radiation. The device plays a role in expanding a depletion region similar to a slope JTE when in reverse operation, so that the blocking voltage of the device is improved under the condition of not changing the structure of the device.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Although the present application has been described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the figures, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (10)
1. A method of preparing a bevel termination PIN diode incorporating a positive surface charge, comprising:
s100, obtaining an N-type substrate;
s200, epitaxially growing an N-epitaxial layer on the surface of the N-type substrate;
s300, epitaxially growing a P region epitaxial layer on the N-epitaxial layer; the N-epitaxial layer and the N-type substrate form a trapezoid table top;
s400, forming a silicon dioxide layer on the trapezoid table top so that the silicon dioxide layer covers the trapezoid table top and the N-type substrate, and performing annealing treatment;
s500, depositing aluminum metal on the silicon dioxide layer, and placing the device obtained by depositing the aluminum metal in a radiation environment to introduce additional positive charges at the interface of silicon dioxide and silicon carbide;
and S600, cleaning aluminum metal on the surface of the silicon dioxide, and etching an opening to form ohmic contact to obtain the inclined plane terminal PIN diode with the surface positive charges introduced.
2. The lead-in table according to claim 1The preparation method of the positive charge inclined plane termination PIN diode is characterized in that the N-type substrate is a SiC substrate, the thickness is 360 mu m, and the doping concentration is 5e18cm -3 -1e20cm -3 。
3. The method for manufacturing a surface positive charge-introducing slope termination PIN diode as recited in claim 1, wherein the doping concentration of the N-epitaxial layer is 1e14cm -3 ～1e16cm -3 。
4. The method for manufacturing a surface positive charge-introducing slope termination PIN diode as recited in claim 1, wherein the doping concentration of the P-region epitaxial layer is 1e16cm -3 ～5e19cm -3 。
5. The method of manufacturing a surface positive charge introducing slope termination PIN diode of claim 1, wherein the thickness of the silicon dioxide layer is 0.5-2 μm.
6. The method of manufacturing a surface-positively charged ramp-terminated PIN diode according to claim 1, wherein the silicon dioxide layer is formed by means of a deposited oxide layer or wet oxidation.
7. The method for preparing a surface positive charge-introduced slope termination PIN diode as recited in claim 1, wherein the annealing treatment in S400 is NO annealing, the annealing temperature is above 1200 ℃ and the time is more than 30min.
8. The method of manufacturing a surface positive charge-introducing slope termination PIN diode of claim 1, wherein S500 comprises:
aluminum metal is deposited on the silicon dioxide layer, and the device obtained by depositing the aluminum metal is placed in a high forward electric field environment with an electric field strength higher than 7MV/cm so as to introduce additional positive charges at the interface between silicon dioxide and silicon carbide.
9. The method of manufacturing a surface positive charge-introducing slope termination PIN diode of claim 1, wherein S500 comprises:
aluminum metal is deposited on the silicon dioxide layer, and the device obtained by depositing the aluminum metal is placed in a low-pressure biased total dose radiation environment for at least more than 10 minutes so as to introduce additional positive charges at the interface of silicon dioxide and silicon carbide.
10. A surface positive charge introducing slope termination PIN diode prepared by the method of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311825529.2A CN117832081A (en) | 2023-12-26 | 2023-12-26 | Inclined plane terminal PIN diode with introduced surface positive charges and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311825529.2A CN117832081A (en) | 2023-12-26 | 2023-12-26 | Inclined plane terminal PIN diode with introduced surface positive charges and preparation method thereof |
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| Publication Number | Publication Date |
|---|---|
| CN117832081A true CN117832081A (en) | 2024-04-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311825529.2A Pending CN117832081A (en) | 2023-12-26 | 2023-12-26 | Inclined plane terminal PIN diode with introduced surface positive charges and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117832081A (en) |
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- 2023-12-26 CN CN202311825529.2A patent/CN117832081A/en active Pending
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