CN113471300A - SiC diode with high forward surge current capability and processing technology - Google Patents
SiC diode with high forward surge current capability and processing technology Download PDFInfo
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- CN113471300A CN113471300A CN202110750007.5A CN202110750007A CN113471300A CN 113471300 A CN113471300 A CN 113471300A CN 202110750007 A CN202110750007 A CN 202110750007A CN 113471300 A CN113471300 A CN 113471300A
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- 238000002347 injection Methods 0.000 claims abstract description 10
- 239000007924 injection Substances 0.000 claims abstract description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 49
- 229910052681 coesite Inorganic materials 0.000 claims description 39
- 229910052906 cristobalite Inorganic materials 0.000 claims description 39
- 239000000377 silicon dioxide Substances 0.000 claims description 39
- 229910052682 stishovite Inorganic materials 0.000 claims description 39
- 229910052905 tridymite Inorganic materials 0.000 claims description 39
- 238000005530 etching Methods 0.000 claims description 17
- 150000002500 ions Chemical class 0.000 claims description 14
- 238000005468 ion implantation Methods 0.000 claims description 11
- 235000012239 silicon dioxide Nutrition 0.000 claims description 10
- 238000000151 deposition Methods 0.000 claims description 9
- 239000010409 thin film Substances 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- 238000001259 photo etching Methods 0.000 claims description 6
- 238000004518 low pressure chemical vapour deposition Methods 0.000 claims description 5
- 239000010408 film Substances 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
- H01L29/861—Diodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
- H01L29/0684—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape, relative sizes or dispositions of the semiconductor regions or junctions between the regions
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
- H01L29/1608—Silicon carbide
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66053—Multistep manufacturing processes of devices having a semiconductor body comprising crystalline silicon carbide
- H01L29/6606—Multistep manufacturing processes of devices having a semiconductor body comprising crystalline silicon carbide the devices being controllable only by variation of the electric current supplied or the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. two-terminal devices
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Abstract
The invention discloses a SiC diode with high forward surge current capability and a processing technology thereof, and the SiC diode comprises a SiC layer (1), wherein a plurality of first grooves (2) are arranged on the SiC layer (1), a second groove (3) is arranged at the upper end of the middle part of each first groove (2), a shallow P + grid layer is filled in each second groove (3), a deep P-grid layer is filled between each first groove (2) and each second groove (3), and an ion injection layer (4) is arranged outside the SiC layer (1). The invention can further improve the forward surge current capability of the SiC diode.
Description
Technical Field
The invention relates to a SiC diode, in particular to a SiC diode with high forward surge current capability and a processing technology thereof.
Background
The SiC diode has higher requirements on forward surge current capability in high-end fields such as photovoltaic, automobiles and the like. The mode of improving the forward surge current capability of the traditional SiC diode is that a SiO2 layer is firstly deposited on the SiC diode, and then photoetching, etching and AL injection are sequentially carried out on a SiO2 layer by utilizing a P-grid photomask, so that a deep P-grid structure is formed on the surface of the SiC diode; and forming a chip working area outside the SiC diode by using the SBD photomask and the Metal photomask through an etching process. The forward surge current capability of the SiC diode can be improved to 8-10 times of the forward current parameter by the process.
With the development of technology and the continuous improvement of SiC diode processing technology by manufacturers, shallow P + grid layers are formed on two sides of the existing deep P-grid layer during the processing of the existing SiC diode, so that the forward surge current capability of the SiC diode is improved to 10-12 times of forward current parameters by utilizing the cooperation of the deep P-grid layer and the shallow P + grid layers on the two sides. Although the forward surge current capability of the diode can be improved compared with that of the traditional SiC diode through the structural improvement, the improvement range is relatively limited, and the pursuit of manufacturers on the performance of the diode is difficult to meet.
Therefore, there is a need for a SiC diode that can further improve the forward surge current capability.
Disclosure of Invention
The invention aims to provide a SiC diode with high forward surge current capability and a processing technology thereof. The forward surge current capability of the SiC diode can be further improved.
The technical scheme of the invention is as follows: the utility model provides a SiC diode of high forward surge current ability, includes the SiC layer, is equipped with a plurality of first grooves on the SiC layer, and the inboard top of first groove is equipped with the second groove, and the second inslot packing has shallow P + grid layer, and it has dark P-grid layer to fill between first groove and the second groove, and the outside on SiC layer is equipped with the ion implantation layer.
In the SiC diode with high forward surge current capability, gaps are left between two sides of the second groove and the first groove.
In the SiC diode with high forward surge current capability, SiO2 layers are arranged on two sides of the connection part of the ion implantation layer and the SiC layer.
In the SiC diode with high forward surge current capability, the depth of the first trench is 1 to 1.2 μm, and the depth of the second trench is 0.3 to 0.5 μm.
In the SiC diode with high forward surge current capability, the width of the first groove is 2.1-3.1 μm, and the width difference between the second groove and the first groove is 0.6 μm.
Based on the processing technology used by the SiC diode with high forward surge current capability, the processing technology comprises the following steps:
firstly, depositing SiO2 on the surface of the SiC layer to form a PE-SiO2 layer outside the SiC layer, and then photoetching and etching the PE-SiO2 layer through a P-grid photomask to form a deep P-grid layer on the surface of the SiC layer to obtain a product A;
depositing a layer of LP-SiO2 thin film on the surface of the product A by LPCVD, and etching the LP-SiO2 thin film to form a Spacer-SiO2 structure to obtain a product B;
injecting AL ions into the surface of the product B to form a shallow P + grid layer on the top of the deep P-grid layer to obtain a product C;
and fourthly, etching the surface of the C product in sequence through an SBD photomask and a Metal photomask, eliminating a Spacer-SiO2 structure and a PE-SiO2 layer above the deep P-grid layer, and forming an ion implantation layer to obtain a finished product.
In the processing technology, the thickness of the LP-SiO2 film layer in the step II is 0.3-0.5 mu m.
In the processing technology, the implantation concentration of the AL ions in the step (c) is 5E 14-1.5E 15.
Compared with the prior art, the shallow P + grid layer is adjusted to the middle part of the deep P-grid layer from two sides of the deep P-grid layer by the conventional SiC diode, so that the current conduction of the SiC diode can be carried out more quickly in a high-temperature environment, and the forward surge current capability of the SiC diode is improved; on the basis, the depth and the width of the shallow P + grid layer and the deep P-grid layer are further optimized, the limit of the injection concentration of the shallow P + grid layer is matched, the improvement effect of the structure can be further improved, the forward surge current capability of the SiC diode can reach 14-16 times of the forward current parameter, and the forward surge current capability of the SiC diode is further improved compared with that of the existing structure. Therefore, the present invention can further improve the forward surge current capability of the SiC diode.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a process flow diagram of the present invention;
fig. 3 is a process flow diagram of a conventional SiC diode.
The labels in the figures are: the structure comprises a 1-SiC layer, a 2-first groove, a 3-second groove, a 4-ion implantation layer, a 5-SiO2 layer, a 6-LP-SiO2 thin film layer, a 7-Spacer-SiO2 structure and a 501-PE-SiO2 layer.
Detailed Description
The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.
Example 1. A SiC diode with high forward surge current capability is formed as shown in figures 1-2 and comprises a SiC layer 1, wherein a plurality of first grooves 2 are formed in the SiC layer 1, second grooves 3 are formed in the upper ends of the middle portions of the first grooves 2, shallow P + grid layers are filled in the second grooves 3, deep P-grid layers are filled between the first grooves 2 and the second grooves 3, and an ion injection layer 4 is arranged outside the SiC layer 1.
Gaps are reserved between the two sides of the second groove 3 and the first groove 2.
And SiO2 layers 5 are arranged on two sides of the joint of the ion implantation layer 4 and the SiC layer 1.
The depth of the first groove 2 is 1-1.2 μm, and the depth of the second groove 3 is 0.3-0.5 μm.
The width of the first trench 2 is 2.1 μm, and the width of the second trench 3 is 1.5 μm.
The processing technology for the SiC diode with high forward surge current capability comprises the following steps:
firstly, depositing SiO2 on the surface of an SiC layer 1 to form a PE-SiO2 layer 501 outside the SiC layer 1, and then photoetching and etching the PE-SiO2 layer 501 through a P-grid photomask to form a deep P-grid layer on the surface of the SiC layer 1 to obtain a product A;
depositing a layer of LP-SiO2 thin film layer 6 on the surface of the product A by LPCVD (low pressure chemical vapor deposition), and then carrying out dry etching on the LP-SiO2 thin film layer 6 to form a Spacer-SiO2 structure 7 to obtain a product B;
injecting AL ions into the surface of the product B to form a shallow P + grid layer on the top of the deep P-grid layer to obtain a product C;
and fourthly, etching the surface of the C product in sequence through an SBD photomask and a Metal photomask, eliminating the Spacer-SiO2 structure 7 and the PE-SiO2 layer 501 above the deep P-grid layer, and forming an ion implantation layer 4 (namely the working area structure of the chip) to obtain a finished product.
In the second step, the thickness of the LP-SiO2 film layer 6 is 0.3-0.5 μm.
And in the step III, the injection concentration of AL ions is 5E 14-1.5E 15.
The working principle of the invention is as follows: firstly, photoetching and etching the surface of an SiC layer 1 to form a deep P-grid layer, and then depositing and etching two sides of a PE-SiO2 layer 501 above the deep P-grid layer to form a Spacer-SiO2 structure 7; and injecting AL ions to form a shallow P + grid layer in the middle of the upper end of the deep P-grid layer, wherein two sides of the upper end of the deep P-grid layer are kept in the original state under the action of the Spacer-SiO2 structure 7. Therefore, the shallow P + grid layer can be positioned at the upper end of the middle part of the deep P-grid layer after being formed, and a gap is formed between the shallow P + grid layer and the first grooves 2 on the two sides. And finally, forming an ion injection layer 4 by etching the SBD photomask and the Metal photomask. When the high-temperature-resistant high-voltage-resistant SiC diode is used, the shallow P + grid layer and the deep P-grid layer are matched in structure, so that the current conduction of the SiC diode can be carried out more quickly in a high-temperature environment, and the forward surge current capability of the high-temperature-resistant high-voltage-resistant SiC diode can reach 14-16 times of forward current parameters.
As shown in fig. 3, a conventional SiC diode is prepared by forming a PE-SiO2 layer 501 on the surface of a SiC layer 1 by photolithography and etching, then implanting AL ions to form a deep P-grid layer 100, and finally forming an ion implantation layer 4 by an SBD mask and a Metal mask by an etching process.
The improved SiC diode manufacturing process is shown in patent 202011123353.2, in which shallow P + grid layers are formed on both sides of a deep P-grid layer, so that the forward surge current capability of the SiC diode is improved by the cooperation of the shallow P + grid layers and the deep P-grid layer.
Example 2. A SiC diode with high forward surge current capability is formed as shown in figures 1-2 and comprises a SiC layer 1, wherein a plurality of first grooves 2 are formed in the SiC layer 1, second grooves 3 are formed in the upper ends of the middle portions of the first grooves 2, shallow P + grid layers are filled in the second grooves 3, deep P-grid layers are filled between the first grooves 2 and the second grooves 3, and an ion injection layer 4 is arranged outside the SiC layer 1.
Gaps are reserved between the two sides of the second groove 3 and the first groove 2.
And SiO2 layers 5 are arranged on two sides of the joint of the ion implantation layer 4 and the SiC layer 1.
The depth of the first groove 2 is 1-1.2 μm, and the depth of the second groove 3 is 0.3-0.5 μm.
The width of the first trench 2 is 3.1 μm, and the width of the second trench 3 is 2.5 μm.
The processing technology for the SiC diode with high forward surge current capability comprises the following steps:
firstly, depositing SiO2 on the surface of an SiC layer 1 to form a PE-SiO2 layer 501 outside the SiC layer 1, and then photoetching and etching the PE-SiO2 layer 501 through a P-grid photomask to form a deep P-grid layer on the surface of the SiC layer 1 to obtain a product A;
depositing a layer of LP-SiO2 thin film layer 6 on the surface of the product A by LPCVD, and then carrying out dry etching on the LP-SiO2 thin film layer 6 to form a Spacer-SiO2 structure 7 to obtain a product B;
injecting AL ions into the surface of the product B to form a shallow P + grid layer on the top of the deep P-grid layer to obtain a product C;
and fourthly, etching the surface of the C product in sequence through an SBD photomask and a Metal photomask, eliminating the Spacer-SiO2 structure 7 and the PE-SiO2 layer 501 above the deep P-grid layer, and forming an ion implantation layer 4 (namely the working area structure of the chip) to obtain a finished product.
In the second step, the thickness of the LP-SiO2 film layer 6 is 0.3-0.5 μm.
And in the step III, the injection concentration of AL ions is 5E 14-1.5E 15.
Claims (8)
1. A kind of SiC diode with high forward surge current ability, characterized by that: including SiC layer (1), be equipped with a plurality of first grooves (2) on SiC layer (1), the middle part upper end of first groove (2) is equipped with second groove (3), and second groove (3) intussuseption is filled with shallow P + grid layer, and it has dark P-grid layer to fill between first groove (2) and second groove (3), and the outside on SiC layer (1) is equipped with ion implantation layer (4).
2. The high forward surge current capability SiC diode of claim 1, wherein: gaps are reserved between the two sides of the second groove (3) and the first groove (2).
3. The high forward surge current capability SiC diode of claim 1, wherein: and SiO2 layers (5) are arranged on two sides of the joint of the ion injection layer (4) and the SiC layer (1).
4. The high forward surge current capability SiC diode of claim 1, wherein: the depth of the first groove (2) is 1-1.2 mu m, and the depth of the second groove (3) is 0.3-0.5 mu m.
5. The high forward surge current capability SiC diode of claim 2, wherein: the width of the first groove (2) is 2.1-3.1 mu m, and the width difference between the second groove (3) and the first groove (2) is 0.6 mu m.
6. A processing technology for the SiC diode with high forward surge current capability based on any one of the claims 1 to 5 is characterized by comprising the following steps:
firstly, depositing SiO2 on the surface of the SiC layer to form a PE-SiO2 layer outside the SiC layer, and then photoetching and etching the PE-SiO2 layer through a P-grid photomask to form a deep P-grid layer on the surface of the SiC layer to obtain a product A;
depositing a layer of LP-SiO2 thin film on the surface of the product A by LPCVD, and etching the LP-SiO2 thin film to form a Spacer-SiO2 structure to obtain a product B;
injecting AL ions into the surface of the product B to form a shallow P + grid layer on the top of the deep P-grid layer to obtain a product C;
and fourthly, etching the surface of the C product in sequence through an SBD photomask and a Metal photomask, eliminating a Spacer-SiO2 structure and a PE-SiO2 layer above the deep P-grid layer, and forming an ion implantation layer to obtain a finished product.
7. The process of claim 6, wherein: in the second step, the thickness of the LP-SiO2 film layer is 0.3-0.5 μm.
8. The process of claim 6, wherein: and in the step III, the injection concentration of AL ions is 5E 14-1.5E 15.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110750007.5A CN113471300A (en) | 2021-07-02 | 2021-07-02 | SiC diode with high forward surge current capability and processing technology |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110750007.5A CN113471300A (en) | 2021-07-02 | 2021-07-02 | SiC diode with high forward surge current capability and processing technology |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20150144966A1 (en) * | 2013-11-26 | 2015-05-28 | Infineon Technologies Ag | Schottky diode with reduced forward voltage |
| CN105990456A (en) * | 2015-03-16 | 2016-10-05 | 株式会社东芝 | Semiconductor device and method for manufacturing the same |
| CN214848637U (en) * | 2021-07-02 | 2021-11-23 | 杭州中瑞宏芯半导体有限公司 | SiC diode with high forward surge current capability |
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2021
- 2021-07-02 CN CN202110750007.5A patent/CN113471300A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20150144966A1 (en) * | 2013-11-26 | 2015-05-28 | Infineon Technologies Ag | Schottky diode with reduced forward voltage |
| CN105990456A (en) * | 2015-03-16 | 2016-10-05 | 株式会社东芝 | Semiconductor device and method for manufacturing the same |
| CN214848637U (en) * | 2021-07-02 | 2021-11-23 | 杭州中瑞宏芯半导体有限公司 | SiC diode with high forward surge current capability |
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