Component gradient composite barrier layer HEMT device and preparation method thereof

Abstract

The invention relates to the field of semiconductor devices, in particular to a component gradient composite barrier layer HEMT (High Electron Mobility Transistor) device and a preparation method of the component gradient composite barrier layer HEMT device. The component gradient composite barrier layer HEMT device comprises a SiC substrate / Si substrate, an AlN nucleating layer, a GaN channel layer, an AlN insertion layer, a gradient Al component AlGaN barrier layer, a fixed Al component AlGaN barrier layer, a source electrode, a drain electrode, a gate electrode and a passivation layer, wherein the thickness of the middle part of the GaN channel layer is greater than the thicknesses of the two sides of the GaN channel layer; the fixed Al component AlGaN barrier layer is adjacent to the gradient Al component AlGaN barrier layer and has the same thickness as the gradient Al component AlGaN barrier layer; according to the invention, the polarization effect of the III-nitride is utilized, and the AlGaN barrier layer with the gradually-changed Al component is adopted under the gate, so that the energy band structure of the semiconductor under the gate can be effectively adjusted, the barrier height is increased, and the gate leakage current is reduced; and meanwhile, the AlGaN barrier layer with the fixed Al component is adopted in the non-gate barrier region, so that the high electron concentration of the channel region can be kept, and the effects of reducing the gate leakage current and keeping the drain output current at a relatively high level are finally achieved.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to a HEMT (High electron mobility transistor, High electron mobility transistor) device and a preparation method thereof. Background technique [0002] The group III nitride heterostructure represented by AlGaN / GaN heterojunction, due to the strong polarization effect induces the formation of a high concentration of two-dimensional electron gas (2-DEG) at the interface of the heterojunction, which is very suitable for the preparation of high electron mobility rate transistors. HEMT devices are widely used in the fields of high-frequency microwave high-power devices, optoelectronic devices and power electronic devices due to the characteristics of high-concentration and high-mobility two-dimensional electron gas. [0003] However, the reliability of AlGaN / GaN HEMT devices has always been a key problem restricting its development, and the gate leakage current is an important fact...

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Problems solved by technology

[0003] However, the reliability of AlGaN / GaN HEMT devices has always been a key problem restricting its development, and the gate leakage current is an important factor

The method of high work function metal can improve the barrier height to a certain extent, but because of the influence of the surface state and other factors, the degree of raising the barrier height through the work function method is limited; the gate dielectric can effectively suppress the gate leakage, but it will Increase the distance between the gate and the channel to reduce the device gate control

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