Regrowth method for reducing interface state of HEMT device by utilizing InN protection layer and HEMT device

Abstract

The invention discloses a regrowth method for reducing an interface state of an HEMT device by utilizing an InN protection layer. After the AlGaN / GaN HEMT structure is grown, an InN protection layer is formed through in-situ epitaxy, when a p-GaN gate structure is regrown by adopting MOCVD, the InN protective layer is evaporated at a high temperature in a growth system, and then the p-GaN layer isextended, so C and O impurity pollution caused by exposure of AlGaN in the air is avoided, and the interface state density of p-GaN / AlGaN can be effectively reduced. When the HEMT device is preparedby the method, the p-GaN layer does not need to be etched, so high source-drain contact resistance or interface damage caused by the fact that the etching depth of the p-GaN layer cannot be accuratelycontrolled in a source-drain region in a traditional method is avoided.

Description

technical field [0001] The invention relates to a regrowth method for reducing the interface state of a HEMT device by using an InN protective layer and the HEMT device, belonging to the technical field of semiconductor devices. Background technique [0002] Semiconductor materials represented by III-V nitrides have the characteristics of large band gap, high electron saturation rate, high critical breakdown electric field, and high channel electron concentration, and can be prepared with lower on-resistance and higher withstand voltage. High Electron Mobility Transistor (HEMT) with higher power density can be widely used in fields such as radio frequency and power electronics. Conventional GaN-based HEMT devices are all depletion-type, and the channel is in the on state at zero bias, which will not only increase the off-state loss of the device and the complexity of the driving circuit, but also reduce the safety of the system. Therefore, there is a stronger demand for enh...

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Problems solved by technology

During the preparation process, the p-GaN outside the gate area is usually removed by dry etching. During the dry etching process, due to the bombardment of the material surface by the plasma, a large number of surface states will be introduced, resulting in serious surface damage. Leakage reduces the breakdown voltage; at the same time, the depth of etching is also difficult to control. Under-etching will lead to large source-drain contact resistance and reduce the output current of the device; if over-etching, it will be introduced on the surface of the AlGaN barrier layer. A large number of interface states reduce device reliability

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