Gallium nitride device schottky contact system with composite metal barrier layer

Abstract

The invention relates to a gallium nitride device schottky contact system with a composite metal barrier layer. The structure of a gallium nitride device successively comprises a substrate 11, a GaN buffer layer 12 and an AlGaN barrier layer 13 from bottom to top; a source electrode 14 is arranged at one end of the upper part of the AlGaN barrier layer; a drain electrode 15 is arranged at the other end of the upper part of the AlGaN barrier layer 13; an AlGaN / GaN HEMT gate electrode 16 is arranged above the AlGaN barrier layer 13 positioned between the source electrode 14 and the drain electrode 15; the AlGaN / GaN HEMT gate electrode 16 is a gate electrode provided with a schottky contact structure; and the schottky contact structure comprises a composite metal layer provided with a Ni metal layer, a Mo metal layer, a Ti metal layer, a Pt metal layer and a Y metal layer. A multi-layered metal system of a schottky gate of the gallium nitride device and an epitaxial layer of the multi-layered metal system have excellent thermal matching property, and reliability of the gallium nitride device can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor device preparation, in particular to a schottky contact system of a gallium nitride device with a composite metal barrier layer. Background technique [0002] Aluminum Gallium Nitride (AlGaN) / Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) is a third-generation wide bandgap compound semiconductor device. What semiconductor technology does not have makes it a unique advantage in leading microwave applications, thus becoming a hot spot in the research of semiconductor microwave power devices. In recent years, researchers have made great breakthroughs in the microwave performance of AlGaN / GaN HEMTs, especially in terms of output power capability. The output power density of the currently disclosed small-size AlGaN / GaN HEMTs can reach more than 30W / mm in the X-band (Wu et al.IEEE Electron Device Lett., Vol.25, No.3, pp.117-119, 2004.), the output power of the Ka band even reached...

AI Technical Summary

Problems solved by technology

When multi-layer metal systems such as Ni / Au / Ti or Ni / Pt / Au / Pt / Ti or Ni / Pt / Au / Ni or Pt / Au / Pt / Ti are used as the Schottky gate of AlGaN / GaN HEMT devices, due to The thickness of the Ni metal layer or Ni / Pt or Pt metal layer is generally about 30-50nm due to its high stress, which makes the Au metal layer on it closer to the epitaxial layer of the AlGaN / GaN HEMT device, and the Au metal layer and AlGaN There is a large thermal mismatch in the epitaxial layer of GaN HEMT devices, which makes the devices have reliability risks when they work at high temperatures

In the semiconductor process, in the multi-layer metal system that can be used as the Schottky gate of AlGaN / GaN HEMT devices, in addition to Au can play a role in reducing the gate resistance of the device, Al or Cu can also be used, but whether it is Au or Al Or Cu, their thermal expansion coefficients are large, and there is a large thermal mismatch with the epitaxial layer of AlGaN / GaN HEMT devices, which is not conducive to the manufacture of high-reliability AlGaN / GaN HEMT devices, so it needs to be improved to reduce Au or GaN HEMT Is it the influence of Al or Cu metals?

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