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CN-116169183-B - N-type silicon carbide-based reverse blocking double-end solid-state thyristors and preparation method thereof

CN116169183BCN 116169183 BCN116169183 BCN 116169183BCN-116169183-B

Abstract

The invention discloses an N-type silicon carbide-based reverse blocking double-end solid-state thyristors and a preparation method thereof, wherein the N-type silicon carbide-based reverse blocking double-end solid-state thyristors comprise: an N + silicon carbide substrate, and a silicon carbide P + anode emitter, a silicon carbide N ‑ drift region and a cathode emitter which are formed by a silicon carbide P base region and a silicon carbide N + region which are sequentially epitaxially grown on the N + silicon carbide substrate. The structure of the cathode emission region is formed by forming a P + implantation window in the silicon carbide N + region and then performing P-type ion implantation to form a silicon carbide cathode P + region in the P + implantation window. The invention makes limitation on the specification of the N base region size and the doping concentration, and through more test verification, on one hand, the high blocking voltage can be realized easily, thereby effectively avoiding the reliability problem caused by series connection, and on the other hand, the invention is beneficial to reducing the thickness of the device, thereby improving the on-state characteristic of the device.

Inventors

  • LIANG LIN
  • QING ZHENGHENG

Assignees

  • 华中科技大学

Dates

Publication Date
20260508
Application Date
20230103

Claims (5)

  1. 1. The N-type silicon carbide-based reverse blocking double-end solid-state thyristors are characterized by sequentially comprising a silicon carbide anode P + emitter region, a silicon carbide N - drift region, a silicon carbide P base region and a cathode emitter region; the structure of the cathode emission region is formed by: And epitaxially growing an N + region in the silicon carbide P base region, forming a P + injection window in the N + region, and performing P-type ion injection to form a silicon carbide cathode P + emitter in the P + injection window.
  2. 2. An N-type silicon carbide-based reverse blocking double-ended solid state thyristor according to claim 1, wherein in the N-type silicon carbide-based reverse blocking double-ended solid state thyristor having a structure of P + N - PP + N + , the anode P + emitter region has a thickness of 1 μm to 3 μm, the doping concentration is 1×10 19 cm -3 ~1×10 20 cm -3 ;N - base region has a thickness of 30 μm to 150 μm, the doping concentration is 1×10 14 cm -3 ~2×10 15 cm -3 , the P drift region has a thickness of 0.8 μm to 4 μm, the doping concentration is 1×10 17 cm -3 ~1×10 18 cm -3 , the cathode N + emitter region has a thickness of 0.5 μm to 2 μm, the doping concentration is 1×10 19 cm -3 ~1×10 20 cm -3 , the width is 15 μm to 25 μm, and the cathode P + emitter region has a thickness of 0.1 μm to 1 μm, the doping concentration is 1×10 19 cm -3 ~1×10 20 cm -3 , and the width is 5 μm to 15 μm.
  3. 3. The preparation method of the N-type silicon carbide-based reverse blocking double-end solid-state thyristors is characterized by comprising the following steps of: S100, sequentially epitaxially growing a silicon carbide anode P + emitter, a silicon carbide N - drift region and a cathode emitter formed by a silicon carbide P base region and a silicon carbide N + on an N + silicon carbide substrate to form an N + P + N - PN + structure; S101, removing the N + silicon carbide substrate and forming a P + N - PN + structure; S102, etching the P + N - PN + structure, forming a P + injection window structure in a cathode N + emission region, and performing P-type ion injection in a cathode N + emission region to form a silicon carbide cathode P+ emission region in the P + injection window; S103, depositing 900nm/35nm/95nm Ni/Ti/Al alloy on the anode of the silicon carbide chip to form an anode contact metal layer, depositing 900nm/35nm/95nm Ni/Ti/Al alloy on the cathode of the silicon carbide chip to form a cathode contact metal layer, carrying out high-temperature annealing treatment on ions injected from a table top, and enabling ohmic contact between each of the anode contact metal layer and the cathode contact metal layer and the silicon carbide-based material; s104, mechanically cutting by utilizing a diamond blade to form a table top with a positive bevel angle of 20-70 degrees on the side surface of the structure, and depositing a silicon dioxide passivation layer to obtain the N-type silicon carbide-based reverse blocking double-end solid-state thyristors with the structure of P + N - PP + N + .
  4. 4. The method of claim 3, wherein in step S102, a mask layer is formed by depositing metallic Ni by magnetron sputtering, stripping is performed by AZ400T or acetone after photolithography, and the P + implantation window is formed by dry etching; or adopting selective ICP etching in mixed gas of fluorinated gas and oxygen at the radio frequency power of 300-600W and under proper working pressure to form the P + injection window.
  5. 5. The method of manufacturing as claimed in claim 3 or 4, wherein the anode P + emitter has a thickness of 1 μm to 3 μm, a doping concentration of 1X 10 19 cm -3 ~1×10 20 cm -3 ;N - base has a thickness of 30 μm to 150 μm, a doping concentration of 1X 10 14 cm -3 ~2×10 15 cm -3 , a P drift region has a thickness of 0.8 μm to 4 μm, a doping concentration of 1X 10 17 cm -3 ~1×10 18 cm -3 , a cathode N + emitter has a thickness of 0.5 μm to 2 μm, a doping concentration of 1X 10 19 cm -3 ~1×10 20 cm -3 , a width of 15 μm to 25 μm, a cathode P + emitter has a thickness of 0.1 μm to 1 μm, a doping concentration of 1X 10 19 cm -3 ~1×10 20 cm -3 , and a width of 5 μm to 15 μm.

Description

N-type silicon carbide-based reverse blocking double-end solid-state thyristors and preparation method thereof Technical Field The invention belongs to the technical field of solid thyristors, and particularly relates to an N-type silicon carbide-based reverse blocking double-end solid thyristors and a preparation method thereof. Background Reverse blocking double ended solid state thyristors (Reverse Blocking Diode Thyristor, RBDT) are two-terminal semiconductor closed switches of a pnpn structure. The RBDT device is initially named a reverse switching rectifier (REVERSE SWITCHING RECTIFIER, RSR), which was initially applied as a switching element for a radar modulator. RBDT the device is a PNPN four layer structure, and during the triggering process, a trigger pulse with a high voltage change rate (dv/dt) needs to be applied between the anode and the cathode. The special trigger mode of RBDT device, which allows the RBDT device to withstand pulse currents with higher current rise rates (di/dt), allows its turn-on process to occur over the entire area of the device. At present, a P long base region structure is adopted in a PNPN layer structure device of more silicon carbide, because if an N long base region is adopted, the P long base region structure needs to be manufactured on a P-type silicon carbide substrate, and under the same doping concentration, the resistivity of the P-type silicon carbide substrate is about two orders of magnitude higher than that of the N-type silicon carbide substrate, so that the forward voltage drop and the on-state loss are not reduced. However, in the actual manufacturing process, the existing control level of defects of SiC materials limits the application development of some power devices. In the epitaxial growth process of the 4H-SiC crystal, various defects are introduced into epitaxial materials by growth conditions, substrate damage, substrate defects and the like, and besides epitaxial growth, the defects are also generated in the processing technology of the device, such as high-temperature annealing, ion implantation, impurity diffusion and the like. For example, impurities and dopant atoms are enriched in the vicinity of dislocations, changing the distribution uniformity of impurities and dopants, and the like. Silicon-based RBDT devices are limited in their application to high voltage and high current applications due to the characteristics of the silicon material. And the high-voltage silicon-based RBDT device has the defects of high conduction voltage drop, high conduction loss and the like. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide an N-type silicon carbide-based reverse blocking double-end solid-state thyristor and a preparation method thereof, and aims to solve the problems of high forward voltage drop and on-state loss caused by adopting a P long base region structure to prepare a PNPN-type thyristor in the prior art. The invention provides an N-type silicon carbide-based reverse blocking double-end solid-state thyristor, which comprises an N + silicon carbide substrate, and a silicon carbide P + anode emitter, a silicon carbide N - drift region, a silicon carbide P base region and a cathode emitter which are sequentially epitaxially grown on the N + silicon carbide substrate. Further, the structure of the cathode emission region is formed by epitaxially growing an N + region in the silicon carbide P base region, forming a P + implantation window in the N + region, and performing P-type ion implantation to form a silicon carbide cathode P + region in the P + implantation window. In the N-type silicon carbide-based reverse blocking double-end solid-state thyristors with the structure of P +N-PP+N+, the thickness of an emitter of an anode P + is 1-3 mu m, the doping concentration is 1X 10 19cm-3～1×1020cm-3;N-, the thickness of a base region is 30-150 mu m, the doping concentration is 1X 10 14cm-3～2×1015cm-3, the thickness of a P drift region is 0.8-4 mu m, the doping concentration is 1X 10 17cm-3～1×1018cm-3, the thickness of an emitter of a cathode N + is 0.5-2 mu m, the doping concentration is 1X 10 19cm-3～1×1020cm-3, the width is 15-25 mu m, the thickness of an emitter of a cathode P + is 0.1-1 mu m, the doping concentration is 1X 10 19cm-3～1×1020cm-3, and the width is 5-15 mu m. Further, the structure of the cathode emission region is formed by ion implantation of silicon carbide N + in the silicon carbide P base region. In the N-type silicon carbide-based reverse blocking double-end solid-state thyristors with the structure of P +N-PN+, the thickness of an emitter of an anode P + is 1-5 mu m, the doping concentration is 1X 10 19cm-3～1×1020cm-3, the thickness of an N-base region is 30-150 mu m, the doping concentration is 1X 10 14cm-3～2×1015cm-3, the thickness of a P drift region is 2-10 mu m, the doping concentration is 1X 10 17cm-3～1×1018cm-3, the thickness of an emitter of a cathode N + is 0.5-2 mu m