CN117219657B - Transverse punching type SiC-TVS device and preparation method thereof - Google Patents
Transverse punching type SiC-TVS device and preparation method thereof Download PDFInfo
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- CN117219657B CN117219657B CN202311470662.0A CN202311470662A CN117219657B CN 117219657 B CN117219657 B CN 117219657B CN 202311470662 A CN202311470662 A CN 202311470662A CN 117219657 B CN117219657 B CN 117219657B
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- 238000002360 preparation method Methods 0.000 title abstract description 8
- 238000004080 punching Methods 0.000 title abstract description 4
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 48
- 229910010271 silicon carbide Inorganic materials 0.000 claims abstract description 47
- 239000000758 substrate Substances 0.000 claims abstract description 17
- 238000009413 insulation Methods 0.000 claims abstract description 15
- 150000002500 ions Chemical class 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 10
- 150000004767 nitrides Chemical class 0.000 claims description 9
- 238000000151 deposition Methods 0.000 claims description 5
- 238000002955 isolation Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000000137 annealing Methods 0.000 claims description 3
- 230000008021 deposition Effects 0.000 claims description 3
- 238000005530 etching Methods 0.000 claims description 3
- 230000000873 masking effect Effects 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 2
- 239000000969 carrier Substances 0.000 abstract description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000001052 transient effect Effects 0.000 description 4
- 230000015556 catabolic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Abstract
The invention discloses a transverse punch-through type SiC-TVS device and a preparation method thereof, wherein the device comprises: a silicon carbide substrate layer; a silicon carbide epitaxial layer; the field insulation areas are uniformly distributed on the silicon carbide epitaxial layer; buffer regions distributed in the silicon carbide epitaxial layer, between and on both sides of the field insulating regions; the transmitting area is positioned in the buffer area; an anode positioned over the end emitter region at one end of the emitter region; and the cathodes are positioned above the end emission areas at the other ends of the emission areas and above the plurality of middle emission areas. The invention provides a transverse punching type SiC-TVS device, which solves the problem of short circuit between an anode and a cathode caused by that carriers gather to break down an oxide layer on the surface of a silicon carbide epitaxial layer when the device works by adding field insulation areas between different emission areas, and increases the reliability and the service life of the device.
Description
Technical Field
The invention relates to a semiconductor device and a preparation method thereof, in particular to a SiC-TVS device and a preparation method thereof.
Background
Transient high energy surge impacts, represented by lightning and electromagnetic pulses, can cause electronic components and downstream electronics to fail or even destroy. Especially in the fields of aerospace, rail transit, high-voltage power grid, advanced weapon system and the like, which are more widely applied in circuit miniaturization and integration, the device-level or circuit system-level damage caused by the abnormal high-energy surge impact needs to be protected. The transient voltage suppression diode (Transient Voltage Suppressor, TVS) has the advantages of high absorption power, high response speed, stable clamping voltage and the like, and is a protective device commonly used at present. When transient surge impact occurs, the TVS is conducted and absorbs surge power in a short time, and the terminal voltage is clamped to a preset value, so that the electronic components/systems are prevented from being damaged by overvoltage or overcurrent impact.
The wide bandgap semiconductor silicon carbide (SiC) material has excellent physical properties, and compared with the traditional Si-based TVS device, the TVS device prepared by using the material has the following advantages: 1) The width of the SiC forbidden band is 3 times that of Si, and the extremely low intrinsic carrier concentration enables the leakage current of the SiC-TVS to be far smaller than that of the Si-TVS, so that the SiC-TVS has excellent blocking property, rigid clamping effect and high resistance Wen Youshi; 2) The critical breakdown electric field of SiC is about 10 times of Si, so that under the same breakdown voltage, the SiC-TVS has smaller drift region thickness, thereby effectively reducing the on-resistance and improving the response speed; 3) The SiC has the thermal conductivity of about 3 times that of Si, and the good thermal conductivity ensures that the device can dissipate heat more quickly at high temperature, thereby improving the reliability; 4) Compared with the common serial-parallel component form of the Si-TVS, the SiC-TVS can obtain the same current or voltage by adopting a single core, thereby saving the system space and improving the reliability. Therefore, siC-TVS having advantages of low leakage, fast response, good thermal conductivity, small size, etc. are getting more and more attention in the field of extremely complex working environments such as high temperature, strong radiation electromagnetic interference, etc.
In the chinese patent application of application number 202211138213.1, a lateral punch-through SiC-TVS device with an optional clamping voltage may implement a bidirectional protection function, as shown in fig. 1, as the carriers of the anode 107 move rightward to the rightmost cathode 108, the lateral electric field thereof decreases gradually, so as to achieve the effect of the optional clamping voltage. However, this device has a disadvantage that in the process of moving carriers from the anode 107 to the cathode 108 in the operating state, carriers gradually accumulate at the interface between the epitaxial layer 102 and the surface oxide layer, and when the carriers accumulate to a certain extent, the surface oxide layer breaks down, so that the anode and the cathode are shorted, resulting in reduced reliability of the device and reduced service life.
Disclosure of Invention
The invention aims to: aiming at the prior art, a transverse punch-through SiC-TVS device and a preparation method thereof are provided, and the problem of surface oxide layer breakdown caused by carrier accumulation in the prior art is solved.
The technical scheme is as follows: a lateral punch-through SiC-TVS device comprising a silicon carbide substrate layer, a silicon carbide epitaxial layer, a plurality of field isolation regions, a plurality of buffer regions, a plurality of emitter regions, an anode and a plurality of cathodes, wherein: the silicon carbide epitaxial layer is positioned on the silicon carbide substrate layer; the field insulation areas are uniformly distributed on the silicon carbide epitaxial layer at intervals; the buffer areas are respectively distributed at two ends of the device and in the silicon carbide epitaxial layer between the field insulating areas; the emitter regions are respectively located in the buffer regions in a one-to-one correspondence manner, and the emitter regions are not in direct contact with the silicon carbide epitaxial layer; the anode is positioned on the surface of an emitting area at one end part of the surface of the device, the cathodes are respectively positioned on the surfaces of the other emitting areas in a one-to-one correspondence manner, and the anode and the cathode are not in direct contact with the buffer area.
Further, each buffer region is connected with the adjacent field insulation region.
Further, the silicon carbide substrate layer is a heavily doped silicon carbide substrate layer of a B conductive type, the silicon carbide epitaxial layer is an epitaxial layer of a lightly doped A conductive type, the buffer region is a buffer region of a lightly doped B conductive type, and the emitter region is an emitter region of a heavily doped B conductive type; if the conductive type A is P-type ions, the conductive type B is N-type ions; if the A conductivity type is N type ion, the B conductivity type is P type ion.
A preparation method of a transverse punch-through type SiC-TVS device comprises the following steps:
step 1: providing a heavily doped silicon carbide substrate layer of a B conductivity type, and epitaxially growing a lightly doped silicon carbide epitaxial layer of an A conductivity type on the surface of the silicon carbide substrate layer of the B conductivity type;
step 2: forming uniformly spaced apart individual ones of said field isolation regions on said silicon carbide epitaxial layer by nitride deposition, nitride masking and etching, partial oxidation and nitride removal;
step 3: lightly doping on the surface of the device to form buffer areas of the conductivity type B;
step 4: heavily doping the surface of the device to form each emission region of the B conductive type;
step 5: depositing metal on the surface of each emission area and forming the anode and the cathode by using an annealing process.
The beneficial effects are that: according to the transverse punching type SiC-TVS device provided by the invention, carriers are not accumulated at the interface of the epitaxial layer and the surface oxide layer as in the prior art by forming the field insulation region, so that the surface oxide layer is not broken down, the problem of short circuit between an anode and a cathode is avoided, and the service life and the reliability of the device are prolonged.
Drawings
Fig. 1 is a schematic diagram of a structure of a conventional lateral punch-through SiC-TVS device;
fig. 2 is a schematic structural diagram obtained through step 1 in the method for manufacturing a lateral punch-through SiC-TVS device according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram obtained through step 2 in the method for manufacturing a lateral punch-through SiC-TVS device according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a lateral through SiC-TVS device manufactured by the method of the present invention through step 3;
fig. 5 is a schematic structural diagram obtained through step 4 in the method for manufacturing a lateral punch-through SiC-TVS device according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a lateral through SiC-TVS device manufactured by the method of the present invention through step 5.
Description of the embodiments
The invention is further explained below with reference to the drawings.
Note that, in this embodiment, "up", "down", "left", "right", "inner" refers to a positional relationship when the SiC-TVS device is in the illustrated state, "long" refers to a lateral dimension when the SiC-TVS device is in the illustrated state, and "deep" refers to a longitudinal dimension when the SiC-TVS device is in the illustrated state.
Referring to fig. 6, fig. 6 is a schematic structural diagram of a lateral through SiC-TVS device according to an embodiment of the present invention. The embodiment of the invention provides a lateral punch-through type SiC-TVS device, which comprises a silicon carbide substrate layer 201 and a silicon carbide epitaxial layer 202; field insulating regions 203-1 to 203-n; a first buffer 204, a second buffer 205; an end emitter region 206, a middle emitter region 207; an anode 208; cathodes 209-1 to 209-n. A silicon carbide epitaxial layer 202 is located over the silicon carbide substrate layer 201; n field insulating regions 203-1 to 203-n are uniformly distributed on the silicon carbide epitaxial layer 202 at intervals; the first buffer areas 204 are respectively distributed at two ends of the device, the second buffer areas 205 are respectively distributed in the silicon carbide epitaxial layer between the field insulation areas, and the buffer areas are respectively connected with the adjacent field insulation areas; two end emission regions 206 are respectively corresponding to the first buffer regions 204 at two ends of the device, each middle emission region 207 is respectively corresponding to the second buffer regions 205, and each emission region is not in direct contact with the silicon carbide epitaxial layer 202; the anode 208 is located on the surface of the end emission region 206 on the left side of the device surface, each cathode 209-1 to 209-n is located on the surface of the rest emission regions in a one-to-one correspondence, and neither the anode 208 nor each cathode 209-1 to 209-n is in direct contact with the buffer region. Wherein n is a positive integer, namely the number of field insulation regions, the number of the field insulation regions is determined according to actual needs, and the larger the range of the required clamping pressure is, the larger the value of n is.
The preparation method of the transverse punch-through type SiC-TVS device comprises the following specific steps:
step 1: as shown in fig. 2, a heavily doped B conductivity type silicon carbide substrate layer 201 is provided, and a lightly doped a conductivity type epitaxial layer 202 is epitaxially grown on the surface of the B conductivity type silicon carbide substrate layer 201.
Step 2: as shown in fig. 3, a number of field insulating regions are formed on the surface of the a conductive type epitaxial layer 202 at uniform intervals by the steps of nitride deposition, nitride masking and etching, local oxidation of specific regions, and nitride removal, where the number of field insulating regions is n, and the number of field insulating regions is, in order from left to right, field insulating region 203-1, field insulating regions 203-2, … …, field insulating region 203- (n-1), and field insulating region 203-n.
Step 3: as shown in fig. 4, two first buffer regions 204 and a plurality of second buffer regions 205 of B conductivity type are formed by lightly doping the device surface, wherein the first buffer regions 204 are located at the left and right ends of the device, the second buffer regions 205 are located between the field insulation regions, and each buffer region is respectively connected with the adjacent field insulation regions.
Step 4: as shown in fig. 5, the surface of the first buffer regions 204 is heavily doped to form end emission regions 206 of B conductivity type, and the surface of the second buffer regions 205 is heavily doped to form intermediate emission regions 207 of B conductivity type, and each emission region is not in direct contact with the silicon carbide epitaxial layer 202.
Step 5: as shown in fig. 6, the rear end process is adopted to form electrodes on the surfaces of the end emission regions 206 and the middle emission region 207 through the steps of metal deposition, annealing and the like, wherein the anode 208 is positioned above the left end emission region 206, the cathodes 209-1 to 209- (n-1) are respectively positioned above the middle emission regions 207 in sequence, the cathode 209-n is positioned above the right end emission region 206, and the anode 208 and the cathodes are not in direct contact with the buffer region.
The principle of the invention is as follows: according to the invention, by adding the field insulation regions between the end emission regions 206 and the adjacent intermediate emission regions 207 and between the intermediate emission regions 207 respectively, the situation that carriers gradually concentrate to the interface between the silicon carbide epitaxial layer 202 and the surface oxide layer breaks down to cause short circuit between the anode and the cathode in the process of moving carriers from the anode 208 to the cathodes in the existing structure is avoided, and thus the reliability of the device and the service life of the device are improved.
Alternatively, if the a conductivity type is P-type ions, the B conductivity type is N-type ions; conversely, if the a conductivity type is N-type ions, the B conductivity type is P-type ions.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (4)
1. A lateral punch-through SiC-TVS device comprising a silicon carbide substrate layer, a silicon carbide epitaxial layer, a plurality of field isolation regions, a plurality of buffer regions, a plurality of emitter regions, an anode, and a plurality of cathodes, wherein: the silicon carbide epitaxial layer is positioned on the silicon carbide substrate layer; the field insulation areas are uniformly distributed on the silicon carbide epitaxial layer at intervals; the buffer areas are respectively distributed at the two ends of the device and in the silicon carbide epitaxial layer between the field insulation areas, and the side surfaces of the buffer areas are respectively connected with the side surfaces of the adjacent field insulation areas; the emitter regions are respectively located in the buffer regions in a one-to-one correspondence manner, and the emitter regions are not in direct contact with the silicon carbide epitaxial layer; the anode is positioned on the surface of an emitting area at one end part of the surface of the device, the cathodes are respectively positioned on the surfaces of the other emitting areas in a one-to-one correspondence manner, and the anode and the cathode are not in direct contact with the buffer area.
2. A lateral punch-through SiC-TVS device according to claim 1, wherein each said buffer region is contiguous with an adjacent said field isolation region.
3. A lateral punch-through SiC-TVS device according to claim 1 or 2, wherein said silicon carbide substrate layer is a heavily doped B conductivity type silicon carbide substrate layer, said silicon carbide epitaxial layer is a lightly doped a conductivity type epitaxial layer, said buffer region is a lightly doped B conductivity type buffer region, said emitter region is a heavily doped B conductivity type emitter region; if the conductive type A is P-type ions, the conductive type B is N-type ions; if the A conductivity type is N type ion, the B conductivity type is P type ion.
4. A method of fabricating a lateral punch-through SiC-TVS device according to claim 3, comprising the steps of:
step 1: providing a heavily doped silicon carbide substrate layer of a B conductivity type, and epitaxially growing a lightly doped silicon carbide epitaxial layer of an A conductivity type on the surface of the silicon carbide substrate layer of the B conductivity type;
step 2: forming uniformly spaced apart individual ones of said field isolation regions on said silicon carbide epitaxial layer by nitride deposition, nitride masking and etching, partial oxidation and nitride removal;
step 3: lightly doping on the surface of the device to form buffer areas of the conductivity type B;
step 4: heavily doping the surface of the device to form each emission region of the B conductive type;
step 5: depositing metal on the surface of each emission area and forming the anode and the cathode by using an annealing process.
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| CN202311470662.0A CN117219657B (en) | 2023-11-07 | 2023-11-07 | Transverse punching type SiC-TVS device and preparation method thereof |
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| CN202311470662.0A CN117219657B (en) | 2023-11-07 | 2023-11-07 | Transverse punching type SiC-TVS device and preparation method thereof |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08125011A (en) * | 1994-09-02 | 1996-05-17 | Mitsubishi Electric Corp | Semiconductor device and its manufacture |
| KR20000031794A (en) * | 1998-11-10 | 2000-06-05 | 김영환 | Method for producing semiconductor device |
| CN101587894A (en) * | 2008-05-16 | 2009-11-25 | 万国半导体股份有限公司 | Electrostatic discharge (esd) protection applying high voltage lightly doped drain (ldd) cmos technologies |
| CN115632056A (en) * | 2022-09-19 | 2023-01-20 | 西安电子科技大学芜湖研究院 | Horizontal punch-through SiC-TVS device with optional clamping voltage |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20080036048A1 (en) * | 2006-08-10 | 2008-02-14 | Vishay General Semiconductor Llc | Semiconductor junction device having reduced leakage current and method of forming same |
| US8860082B2 (en) * | 2012-07-15 | 2014-10-14 | Richtek Technology Corporation, R.O.C. | Transient voltage suppressor circuit, and diode device therefor and manufacturing method thereof |
| US10930636B2 (en) * | 2018-08-20 | 2021-02-23 | Amazing Microelectronic Corp. | Transient voltage suppression device |
| CN111312707B (en) * | 2020-02-27 | 2022-11-04 | 电子科技大学 | Power semiconductor device with low specific on-resistance |
| US20230170384A1 (en) * | 2021-11-29 | 2023-06-01 | Texas Instruments Incorporated | High voltage avalanche diode for active clamp drivers |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08125011A (en) * | 1994-09-02 | 1996-05-17 | Mitsubishi Electric Corp | Semiconductor device and its manufacture |
| KR20000031794A (en) * | 1998-11-10 | 2000-06-05 | 김영환 | Method for producing semiconductor device |
| CN101587894A (en) * | 2008-05-16 | 2009-11-25 | 万国半导体股份有限公司 | Electrostatic discharge (esd) protection applying high voltage lightly doped drain (ldd) cmos technologies |
| CN115632056A (en) * | 2022-09-19 | 2023-01-20 | 西安电子科技大学芜湖研究院 | Horizontal punch-through SiC-TVS device with optional clamping voltage |
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Effective date of registration: 20240222 Address after: No. 88, Wenchang East Road, Yangzhou, Jiangsu 225000 Patentee after: Jiangsu Daoyuan Technology Group Co.,Ltd. Country or region after: China Address before: 211135 enlightenment star Nanjing maker space G41, second floor, No. 188, Qidi street, Qilin science and Technology Innovation Park, Qixia District, Nanjing, Jiangsu Province Patentee before: Jiangsu Peregrine Microelectronics Co.,Ltd. Country or region before: China |