Preparation method of GaN-based p-type grid structure

Abstract

The invention provides a preparation method of a GaN-based p-type grid structure. The preparation method comprises the following steps: coating the surface of a gallium nitride based material with a photoresist, and photoetching the pattern of an area to be etched; etching by using a dry method, taking the photoresist as a mask, etching a GaN cap layer and a p-type grid layer with 90% thickness inan exposed area, and removing remaining photoresist; carrying out oxidation treatment on the treated gallium nitride based material; putting the gallium nitride based material into a corrosive solution for etching so as to obtain the GaN-based p-type grid structure. According to the method, the preparation of the GaN-based p-type grid structure is completed by adopting mixed etching of dry methodand wet method; the problem of surface damage caused by dry method etching is solved through wet method etching, and the uniformity of etching depth is guaranteed through self-stop characteristic; and the thickness of etching required by wet etching is obviously reduced through dry method etching, so that the oxidation and etching time required by using wet method etching purely can be greatly reduced, the efficiency is improved, the side etching effect is reduced preferably, and the technological controllability is guaranteed.

Description

technical field [0001] The invention relates to the semiconductor technical field of GaN-based (GaN) materials and devices, in particular to a preparation method of a GaN-based p-type gate structure. Background technique [0002] Devices based on AlGaN / GaN, InGaN / GaN, InAlGa / GaN, etc. are collectively referred to as gallium nitride-based devices, such as AlGaN / GaN heterostructure field effect transistors (heterostructure field effect transistors, HFET), heterojunction bipolar Transistor (heterostructure bipolar transistor, HBT), etc. Gallium nitride-based devices have the advantages of strong breakdown field, high electron mobility, and high saturation speed. They are considered to be strong competitors for the next generation of power switching devices, and have been favored by researchers in recent years. [0003] However, due to the strong spontaneous polarization and piezoelectric polarization effects of the heterojunction structure in the above material system, GaN-bas...

AI Technical Summary

Problems solved by technology

However, at present, the preparation of p-type gate structure still adopts dry etching technology based on inductive coupling (ICP) or reactive ion etching (RIE). On the one hand, dry etching is easy to cause damage to the GaN surface and cause device performance degradation; On the other hand, dry etching is difficult to control the etching rate and the etching depth is inconsistent, resulting in poor consistency of device characteristics within and between chips, thereby reducing the yield of GaN products

On the other hand, the wet etching technology for the p-type gate structure is still immature. At the same time, the wet etching process will inevitably introduce lateral corrosion, which will affect the controllability of the device process.

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