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CN-116206976-B - High-voltage Schottky diode with vertical AlGaN/GaN heterojunction and preparation method thereof

CN116206976BCN 116206976 BCN116206976 BCN 116206976BCN-116206976-B

Abstract

The invention relates to a high-voltage Schottky diode with a vertical AlGaN/GaN heterojunction and a preparation method thereof, wherein the preparation method comprises the following steps of growing epitaxial materials; second, the re-growth groove is manufactured and re-grown, third, the cathode is manufactured, fourth, the medium layer is grown, fifth, the anode is manufactured. The diode can obviously improve the forward current of the diode by utilizing the 2DEG (two-dimensional electron gas) in the vertical direction formed by the regrowth, and can uniformly disperse the peak electric field by utilizing the PN junction formed by the regrowth, improve the electric field concentration effect and improve the breakdown voltage, and in the reverse direction, the PN junction can reduce the reverse electric leakage more effectively than a Schottky junction.

Inventors

  • BAI JUNCHUN
  • CHENG BIN
  • Ping Jiafeng
  • WANG FUJIN

Assignees

  • 江苏芯港半导体有限公司

Dates

Publication Date
20260512
Application Date
20230324

Claims (9)

  1. 1. The preparation method of the high-voltage Schottky diode with the vertical AlGaN/GaN heterojunction is characterized by comprising the following steps of: 1) Growing a P-GaN layer (2) with the thickness of 3-9 mu m on the front surface of the N + -GaN layer (1) with the thickness of 1-4 mu m; 2) Etching grooves (a) on the N + -GaN layer (1) and the P-GaN layer (2), wherein the width of the grooves (a) is 3-5 mu m, and the depth is 100-500 nm of the N + -GaN layer (1) in an etching way; 3) Integrally growing an N - -GaN layer (3) with the thickness of 100-500 nm; 4) Growing an AlGaN layer (4) with the thickness of 10-30 nm on the N - -GaN layer (3); 5) Manufacturing a cathode (5) on the bottom surface of the N + -GaN layer (1); 6) Depositing a dielectric layer (6) with the thickness of 0.2-1 mu m on the AlGaN layer (4); 7) Etching away part of the N - -GaN layer (3), the AlGaN layer (4) and the dielectric layer (6) which are positioned on the P-GaN layer (2) to expose the top surface of the P-GaN layer (2); 8) Etching an anode groove (c) on the exposed top surface of the P-GaN layer (2), wherein the depth of the anode groove (c) is 300-900nm; 9) And manufacturing an anode (7) in the anode groove (c), on the rest of the dielectric layer (6) and on part of the P-GaN layer (2).
  2. 2. The method for manufacturing the high-voltage schottky diode with the vertical AlGaN/GaN heterojunction according to claim 1, wherein the Al composition of the AlGaN layer (4) is 15% -40%.
  3. 3. The method for manufacturing a high voltage schottky diode with a vertical AlGaN/GaN heterojunction according to claim 2, wherein the dielectric layer (6) is an Al 2 O 3 layer, a SiN layer or a SiO 2 layer.
  4. 4. The method of manufacturing a high voltage schottky diode with vertical AlGaN/GaN heterojunction as claimed in claim 3, wherein two-dimensional electron gas (b) is formed between the AlGaN layer (4) and the N - -GaN layer (3) in the vertical direction and two-dimensional electron gas is not formed in the horizontal direction.
  5. 5. The method of manufacturing a high voltage schottky diode with vertical AlGaN/GaN heterojunction as defined in claim 4, wherein a PN junction is formed between the N - -GaN layer (3) and the P-GaN layer (2).
  6. 6. The method for manufacturing a high voltage schottky diode with a vertical AlGaN/GaN heterojunction according to claim 5, wherein the cathode (5) is formed by stacking a Ti layer, an Al layer, a Ni layer and an Au layer, wherein the Ti layer has a thickness of 20nm, the Al layer has a thickness of 160nm, the Ni layer has a thickness of 55nm and the Au layer has a thickness of 45nm.
  7. 7. The method of manufacturing a high voltage schottky diode with vertical AlGaN/GaN heterojunction according to claim 6, wherein after said step 5), a rapid metal annealing treatment is performed, said rapid metal annealing treatment being a rapid thermal annealing at 870 ℃ in an N 2 atmosphere for 30 s.
  8. 8. The method for manufacturing a high voltage schottky diode with a vertical AlGaN/GaN heterojunction according to claim 7, wherein the anode (7) is formed by laminating a Ni layer and an Au layer, wherein the thickness of the Ni layer is 45nm, and the thickness of the Au layer is 200nm.
  9. 9. A high voltage schottky diode with vertical AlGaN/GaN heterojunction, characterized in that it is prepared by the preparation method of any one of claims 1 to 8.

Description

High-voltage Schottky diode with vertical AlGaN/GaN heterojunction and preparation method thereof Technical Field The invention belongs to the technical field of microelectronic devices, relates to a GaN-based Schottky diode and a preparation method thereof, and in particular relates to a high-voltage Schottky diode with a vertical AlGaN/GaN heterojunction and a preparation method thereof. Background The development of the semiconductor industry has provided an indispensable pushing effect for the social development and progress until now. In particular, as semiconductor technology is mature, third generation semiconductor materials represented by GaN, siC and semiconductor diamond are coming up, and are becoming a research hotspot in the semiconductor industry with more obvious advantages over the former two generations of semiconductor materials. GaN materials have been rapidly developed over the last twenty years from the first time they were proposed and the third generation semiconductor devices associated therewith have found wide application. Among them, a third generation wide band gap semiconductor material typified by gallium nitride (GaN) is increasingly emerging. Compared with the traditional semiconductor material, gaN has good chemical stability, high breakdown voltage, low on-resistance and higher working temperature. These advantages are greatly remedied the inherent deficiencies of conventional semiconductor materials. Therefore, the GaN device can operate in a high-temperature, high-power, high-frequency environment. At present, schottky diodes are evolving towards high breakdown voltage, high switching ratio, low on-resistance. The high breakdown voltage can ensure the stability of the device under high voltage, the high switching ratio can ensure that the device can realize better switching action, and the low on-resistance can realize low on-loss. Aiming at the condition that the gallium nitride Schottky diode (Schottky Barrier Diode, abbreviated as SBD) has low breakdown voltage, the gallium nitride Schottky diode with the vertical structure can effectively improve the breakdown voltage compared with the gallium nitride Schottky diode with the transverse structure. However, the vertical junction barrier schottky (junction barrier schottky) diode prepared by the prior art still has the problems of low withstand voltage, large reverse leakage current, small forward current and the like. In view of the above-mentioned technical drawbacks of the prior art, there is a need to provide an improved high voltage schottky diode and a method for manufacturing the same, which overcome the above-mentioned drawbacks. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides a high-voltage Schottky diode with a vertical AlGaN/GaN heterojunction and a preparation method thereof, which can solve the problems of low withstand voltage, large reverse leakage current, small forward current and the like of a vertical junction barrier Schottky (junction barrier schottky) diode prepared by the prior art. In order to achieve the above object, the present invention provides the following technical solutions: The preparation method of the high-voltage Schottky diode with the vertical AlGaN/GaN heterojunction is characterized by comprising the following steps of: 1) Growing a P-GaN layer with the thickness of 3-9 mu m on the front surface of the N + -GaN layer with the thickness of 1-4 mu m; 2) Etching grooves on the N + -GaN layer and the P-GaN layer, wherein the width of the grooves is 3-5 mu m, and the depth of the grooves is 100-500 nm when the N + -GaN layer is etched; 3) Integrally growing an N - -GaN layer with the thickness of 100-500 nm; 4) Growing an AlGaN layer with the thickness of 10-30nm on the N - -GaN layer; 5) Manufacturing a cathode on the bottom surface of the N + -GaN layer; 6) Depositing a dielectric layer with the thickness of 0.2-1 mu m on the AlGaN layer; 7) Etching away part of the N - -GaN layer, the AlGaN layer and the dielectric layer which are positioned on the P-GaN layer to expose the top surface of the P-GaN layer; 8) Etching an anode groove on the top surface of the exposed P-GaN layer, wherein the depth of the anode groove is 300-900nm; 9) And manufacturing an anode in the anode groove, on the rest of the dielectric layer and on part of the P-GaN layer. Preferably, the Al component of the AlGaN layer is 15% -40%. Preferably, the dielectric layer is an Al 2O3 layer, a SiN layer or a SiO 2 layer. Preferably, a two-dimensional electron gas is formed between the AlGaN layer and the N - -GaN layer in a vertical direction and a two-dimensional electron gas is not formed in a horizontal direction. Preferably, a PN junction is formed between the N - -GaN layer and the P-GaN layer. Preferably, the cathode is formed by stacking a Ti layer, an Al layer, a Ni layer and an Au layer, wherein the thickness of the Ti layer is 20nm, the thickness of the Al