A novel n-i-p-n half-mesa vertical silicon carbide avalanche diode and its preparation method

Abstract

The invention discloses a silicon carbide avalanche diode of a novel n-i-p-n half-mesa vertical structure and a preparation method thereof. According to the invention, the silicon carbide avalanche diode is of a n-i-p-n structure and sequentially comprises a lower metal contact electrode, an n-type conductive SiC substrate, a p-type SiC contact layer, an i-type SiC avalanche layer, an n-type SiC transition layer, an n+ type SiC contact layer and an upper metal contact electrode from bottom to top. The n-type SiC transition layer and the n+ type SiC contact layer form a mesa type large in bottom and small in top. The area of the lower surface of the n-type SiC transition layer is smaller than the area of the upper surface of the i-type SiC avalanche layer. A passivation layer is respectively arranged at the periphery of the n-type SiC transition layer, the periphery of the n+ type SiC contact layer and the upper surface of the i-type SiC avalanche layer which is not covered by the n-type SiC transition layer. According to the invention, the etching damage is reduced, so that the cost performance of the device is improved. The device can adopt n-type ohmic contact with better quality, so that the working efficiency of the device is improved. The avalanche noise is reduced, and the number of lead-out wires is reduced. The cost of the device is reduced.

Description

technical field [0001] The invention relates to a novel n-i-p-n half-mesa vertical structure silicon carbide avalanche diode and a preparation method thereof, belonging to the field of silicon carbide avalanche diodes. Background technique [0002] As one of the representatives of the third-generation wide bandgap semiconductors, silicon carbide (SiC) has excellent characteristics such as wide band gap, high breakdown field strength, high electron saturation velocity, high thermal conductivity, and good chemical stability. In recent years, with a large amount of research and development investment in SiC materials at home and abroad, the material quality and manufacturing process technology have been significantly improved, making it the preferred material for the preparation of high-power, high-temperature, and high-efficiency ultraviolet avalanche detector devices (APD). Among them, the 4H-SiC semiconductor material has a band gap of 3.26eV, which is the preferred material...

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Problems solved by technology

[0007] In order to solve the problems of low working efficiency, large avalanche multiplication noise, and poor quality of p-type ohmic contact in traditional p-i-n type SiC APDs, as well as the need to use p-type silicon carbide substrates that are expensive and not yet commercialized in traditional n-i-p type SiC APDs, engraved In view of the problems of large etching depth, serious etching damage, large number of lead wires, and high manufacturing cost, the present invention provides a novel n-i-p-n half-mesa vertical structure silicon carbide avalanche diode and its preparation method

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