CN113903790B - Silicon carbide schottky device with composite groove structure - Google Patents
Silicon carbide schottky device with composite groove structure Download PDFInfo
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- CN113903790B CN113903790B CN202111219525.0A CN202111219525A CN113903790B CN 113903790 B CN113903790 B CN 113903790B CN 202111219525 A CN202111219525 A CN 202111219525A CN 113903790 B CN113903790 B CN 113903790B
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- silicon carbide
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- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 57
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 42
- 239000002131 composite material Substances 0.000 title claims abstract description 12
- 238000002347 injection Methods 0.000 claims abstract description 19
- 239000007924 injection Substances 0.000 claims abstract description 19
- 230000007704 transition Effects 0.000 claims description 27
- 239000002184 metal Substances 0.000 claims description 20
- 230000001629 suppression Effects 0.000 claims description 10
- 150000001875 compounds Chemical class 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 5
- 239000012535 impurity Substances 0.000 abstract description 4
- 230000008569 process Effects 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 230000005764 inhibitory process Effects 0.000 abstract 2
- 238000002513 implantation Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 230000003211 malignant effect Effects 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/0603—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 particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions
- H01L29/0607—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 particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration
- H01L29/0611—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 particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices
- H01L29/0615—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 particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE]
- H01L29/0619—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 particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/872—Schottky diodes
Abstract
The invention belongs to the technical field of silicon carbide Schottky devices, in particular to a silicon carbide Schottky device with a composite groove structure, which comprises a silicon carbide layer N+, an N-type ohmic contact layer formed on the back surface of the silicon carbide layer N+ and a silicon carbide outer edge layer N-formed on the silicon carbide layer N+, wherein a current inhibition area is arranged on the silicon carbide outer edge layer N-, grooves are carved on the surface of the corresponding silicon carbide outer edge layer N-in the current inhibition area, and P-type protection rings are formed on the bottom corners and the side walls of the grooves through injection doping. According to the invention, the top angle of the groove is set to be an open structure, so that the injection doping height of the groove is reduced as a whole, the influence of the too high side wall of the groove on the injection depth of the doped impurities injected by the injection equipment is reduced to a large extent, the groove with the increased curvature radius at the bottom angle and the non-increased width of the groove can be realized under the condition of the same manufacturing capability, the performance of higher reverse working withstand voltage can be obtained, and the method has high reliability and low process complexity.
Description
Technical Field
The invention relates to the technical field of silicon carbide schottky devices, in particular to a silicon carbide schottky device with a composite groove structure.
Background
The silicon carbide material is used as a third-generation semiconductor material and is used as a wide forbidden band material, and has the characteristics of high breakdown field intensity, high thermal conductivity and high saturation speed, so that the silicon carbide device has the characteristics of high voltage, high speed and high efficiency, and becomes a new development choice. The silicon carbide Schottky device belongs to a unipolar device, has extremely short reverse recovery time, can be widely applied to a high-frequency rectifying circuit, has the characteristic of low forward saturation voltage drop, has low power consumption, and is widely applied. The traditional silicon-based Schottky device can only be used for products below 300V due to the limitation of reverse working voltage, so that the application range of the traditional silicon-based Schottky device is limited; the reverse working voltage of the silicon carbide Schottky device can reach 3300V, the working voltage range of the Schottky device is supplemented, namely, the silicon carbide Schottky device expands the application field of the Schottky device, so that the Schottky device can work in a higher working voltage range.
The P-type region of the current trench structure is generally doped at the same time by adopting the side wall and the bottom, injection is realized by realizing injection angle change scanning or carrying platform revolution and self-transmission, and higher requirements are also put forward on injection equipment.
Disclosure of Invention
(one) solving the technical problems
Aiming at the defects of the prior art, the invention provides a silicon carbide Schottky device with a composite groove structure, which solves the problems that the deeper the groove, the higher the injection requirement is, the higher the equipment and process requirement is and the higher the difficulty is, because the silicon carbide Schottky device with a composite groove structure solves the problems that the P-type region of the groove structure of the traditional silicon carbide Schottky device is generally doped by the side wall and the bottom, the injection is required to realize the injection angle change scanning or the carrier revolution and self-transmission are realized, and higher the requirement is also put forward on injection equipment.
(II) technical scheme
The invention adopts the following technical scheme for realizing the purposes:
the utility model provides a carborundum schottky device with compound trench structure, includes carborundum layer N+, forms in carborundum layer N+ the N type ohmic contact layer on the back and forms in carborundum layer N+ on carborundum layer N-, be equipped with the electric current suppression district on the carborundum epitaxial layer N-, correspond carborundum epitaxial layer N-surface and carved with the slot in the electric current suppression district, be formed with P type guard ring through the injection doping on the base angle and the lateral wall of slot, the apex angle department of slot is equipped with the opening, correspond in the slot and be filled with P type carborundum, correspond the open top on carborundum epitaxial layer N-and be equipped with N type guard ring, the outside interval of N type guard ring is equipped with schottky metal layer, connects through the insulating layer between two adjacent schottky metal layers, schottky metal layer and insulating layer's outside cover has the positive pole metal layer, the edge that the electric current suppression district was equipped with N type transition district, the edge that the electric current suppression district was kept away from to N type transition district is equipped with P type well district.
Further, the anode metal layer also covers the upper surfaces of the N-type transition region and the P-type well region.
Further, a transition region notch is formed in the N-type transition region corresponding to the silicon carbide epitaxial layer N-, the groove wall interval width of the transition region notch is larger than the groove wall interval width of the groove, and a transition region P-type protection ring is formed on the bottom corner and the side wall of the transition region notch through injection doping.
Further, a well region notch is formed in the P-type well region corresponding to the silicon carbide epitaxial layer N-, the wall interval width of the well region notch is equal to the wall interval width of the groove, and a well region P-type protection ring is formed on the bottom corner and the side wall of the well region notch through injection doping.
(III) beneficial effects
Compared with the prior art, the invention provides a silicon carbide Schottky device with a composite groove structure, which has the following beneficial effects:
according to the invention, the top angle of the groove is set to be an open structure, so that the injection doping height of the groove is reduced as a whole, the influence of the too high side wall of the groove on the injection depth of the doped impurities injected by the injection equipment is reduced to a large extent, the groove with the increased curvature radius at the bottom angle and the non-increased width of the groove can be realized under the condition of the same manufacturing capability, the performance of higher reverse working withstand voltage can be obtained, and the method has high reliability and low process complexity.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic diagram showing the position marks of the current suppressing region, the N-type transition region and the P-type well region according to the present invention.
In the figure: 1. a groove; 2. a P-type protection ring; 3. p-type silicon carbide; 4. an N-type protection ring; 5. a schottky metal layer; 6. an insulating layer; 7. an anode metal layer; 8. an N-type transition region; 9. a P-type well region; 10. and (3) opening.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Examples
As shown in fig. 1-2, a silicon carbide schottky device with a composite trench structure provided by an embodiment of the present invention includes a silicon carbide layer n+, an N-type ohmic contact layer formed on the back surface of the silicon carbide layer n+ and a silicon carbide epitaxial layer N-formed on the silicon carbide layer N-, wherein a current suppressing region is provided on the silicon carbide epitaxial layer N-, a trench 1 is engraved on the surface of the corresponding silicon carbide epitaxial layer N-in the current suppressing region, a P-type guard ring 2 is formed on the bottom corner and the sidewall of the trench 1 by implantation doping, in order to solve the problem of the depth of the trench 1 due to the shielding of the sidewall of the trench 1, an opening 10 is provided at the top corner of the trench 1, an N-type guard ring 4 is correspondingly filled in the trench 1, and the P-type guard ring 2 vertically corresponds to each other, and by setting the top corner of the trench 1 as an open 10 structure, the trench 1, the P-type 2, the open 10 and the N-type guard ring 4 form the composite trench 1 structure, the implantation doping height of the trench 1 is reduced, and the implantation depth of the impurity is greatly reduced on the sidewall of the trench 1, and the implantation depth is greatly influenced by the implantation depth of the impurity is greatly; the N-type protection ring 4 is provided with Schottky metal layers 5 at intervals outside, two adjacent Schottky metal layers 5 are connected through an insulating layer 6, the insulating layer 6 can be made of polyimide material, the thickness of the insulating layer 6 is the same as that of the Schottky metal layers 5, and because the Schottky metal layers 5 are separated by the insulating layer 6, current flows through the device in a parallel manner, so that the positive feedback phenomenon of malignant current caused by uneven local current due to the large-piece metal adhesion effect is relieved, the device works more stably, the reliability is high, and the service life is long; the outside of schottky metal layer 5 and insulating layer 6 is covered and is had positive pole metal layer 7, and the edge of electric current suppression district is equipped with N type transition district 8, and the setting of N type transition district 8 can keep stable blocking voltage and do not take place the drift under the stress of high temperature high pressure, effectively improves the reliability of device, and the edge that N type transition district 8 kept away from the electric current suppression district is equipped with P type well region 9.
In this embodiment, the P-type guard ring 2 and the N-type guard ring 4 are formed by chemical vapor deposition epitaxial growth, so that lattice damage caused by multiple ion implantation can be avoided; the ratio control of the P-type guard ring 2 in the trench 1 to the P-type silicon carbide 3 filled in the trench 1 and the depth and width of the trench 1 can be determined according to the requirements of the actual forward conduction characteristics and reverse breakdown characteristics.
In another aspect of this embodiment, the thickness of the portion of the P-type guard ring 2 corresponding to the bottom corner of the trench 1 is greater than the thickness of the portion of the P-type guard ring 2 corresponding to the sidewall of the trench 1, and this structural design helps to increase the switching efficiency of the device in high frequency applications.
In some embodiments, as shown in fig. 1, the anode metal layer 7 also covers the upper surfaces of the N-type transition region 8 and the P-type well region 9.
As shown in fig. 1, in some embodiments, a transition region notch is formed on the N-type transition region 8 corresponding to the silicon carbide epitaxial layer N-, the groove wall interval width of the transition region notch is greater than the groove wall interval width of the groove 1, and a transition region P-type protection ring is formed on the bottom corner and the side wall of the transition region notch by implantation doping.
As shown in fig. 1, in some embodiments, a well region notch is formed on the P-type well region 9 corresponding to the silicon carbide epitaxial layer N-, the wall interval width of the well region notch is equal to the wall interval width of the trench 1, and a well region P-type protection ring is formed on the bottom corner and the side wall of the well region notch through implantation doping.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. The utility model provides a carborundum schottky device with compound trench structure, includes carborundum layer N+, forms the N type ohmic contact layer in carborundum layer N+ back and forms carborundum epitaxial layer N-on carborundum layer N+, its characterized in that: the silicon carbide epitaxial layer N-is gone up and is equipped with electric current suppression district, electric current suppression district corresponds silicon carbide epitaxial layer N-surface and is carved with slot (1), be formed with P type guard ring (2) through injecting doping on the base angle and the lateral wall of slot (1), the apex angle department of slot (1) is equipped with uncovered (10), correspond in slot (1) to be filled with P type carborundum (3), correspond uncovered (10) top on the silicon carbide epitaxial layer N-and be equipped with N type guard ring (4), the outside interval of N type guard ring (4) is equipped with schottky metal layer (5), connects through insulating layer (6) between two adjacent schottky metal layers (5), the outside cover of schottky metal layer (5) and insulating layer (6) has positive pole metal layer (7), the edge in electric current suppression district is equipped with N type transition district (8), the edge that current suppression district was kept away from to N type transition district (8) is equipped with P type trap district (9).
2. A silicon carbide schottky device with a composite trench structure according to claim 1 wherein: the anode metal layer (7) also covers the upper surfaces of the N-type transition region (8) and the P-type well region (9).
3. A silicon carbide schottky device with a composite trench structure according to claim 1 wherein: the N-type transition region (8) is internally provided with a transition region notch corresponding to the silicon carbide epitaxial layer N-, the groove wall interval width of the transition region notch is larger than the groove wall interval width of the groove (1), and a transition region P-type protection ring is formed on the bottom corner and the side wall of the transition region notch through injection doping.
4. A silicon carbide schottky device with a composite trench structure according to claim 1 wherein: the P-type well region (9) is internally provided with a well region notch corresponding to the silicon carbide epitaxial layer N-, the groove wall interval width of the well region notch is equal to the groove wall interval width of the groove (1), and a well region P-type protection ring is formed on the bottom angle and the side wall of the well region notch through injection doping.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111219525.0A CN113903790B (en) | 2021-10-20 | 2021-10-20 | Silicon carbide schottky device with composite groove structure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111219525.0A CN113903790B (en) | 2021-10-20 | 2021-10-20 | Silicon carbide schottky device with composite groove structure |
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| Publication Number | Publication Date |
|---|---|
| CN113903790A CN113903790A (en) | 2022-01-07 |
| CN113903790B true CN113903790B (en) | 2023-11-07 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009177028A (en) * | 2008-01-25 | 2009-08-06 | Toshiba Corp | Semiconductor apparatus |
| CN109509795A (en) * | 2018-12-20 | 2019-03-22 | 上海芯石半导体股份有限公司 | A kind of silicon carbide schottky devices and its manufacturing method with composite trench structure |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI376752B (en) * | 2008-04-22 | 2012-11-11 | Pfc Device Co | Mos pn junction schottky diode and method for manufacturing the same |
| TWI469221B (en) * | 2009-06-26 | 2015-01-11 | Pfc Device Co | Trench schottky diode and manufacturing mehtod thereof |
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- 2021-10-20 CN CN202111219525.0A patent/CN113903790B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009177028A (en) * | 2008-01-25 | 2009-08-06 | Toshiba Corp | Semiconductor apparatus |
| CN109509795A (en) * | 2018-12-20 | 2019-03-22 | 上海芯石半导体股份有限公司 | A kind of silicon carbide schottky devices and its manufacturing method with composite trench structure |
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| CN113903790A (en) | 2022-01-07 |
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