Method for preparing enhanced aluminum-gallium-nitrogen/gallium nitride transistor with high electron mobility

Abstract

The invention discloses a method for preparing enhanced aluminum-gallium-nitrogen / gallium nitride transistor with high electron mobility. The method comprises the following steps: growing a gallium nitride nucleation layer on a substrate; growing a gallium nitride buffer layer on the gallium nitride nucleation layer; growing a high-mobility gallium nitride layer on the gallium nitride buffer layer; growing an aluminum nitride insertion layer on the high-mobility gallium nitride layer; growing an aluminum-gallium-nitrogen barrier layer on the aluminum nitride insertion layer; growing an indium nitride capping layer on the aluminum-gallium-nitrogen barrier layer; etching the indium nitride capping layer; preparing source-drain ohmic contact; preparing gate metal; and thickening electrode metal. The method has the advantages of reducing preparation cost, simplifying preparation process and improving process reliability.

Description

technical field [0001] The invention relates to the technical field of semiconductor material growth and device preparation, in particular to a method for preparing an enhanced aluminum gallium nitride / gallium nitride high electron mobility transistor. The shape of the energy band of the gallium heterojunction depletes the two-dimensional electron gas at the interface of the heterojunction and realizes the enhanced working mode of the device. Background technique [0002] As a typical representative of the third-generation wide-bandgap semiconductor materials, gallium nitride has high critical breakdown electric field, high electron saturation drift velocity, excellent thermal stability, chemical stability, and strong radiation resistance. A hotspot of competing research. Due to spontaneous polarization and piezoelectric polarization, the concentration of two-dimensional electron gas formed at the AlGaN / GaN heterojunction interface reaches 10 13 cm -2 , mobility up to 200...

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Problems solved by technology

However, due to the extremely low concentration of two-dimensional electron gas in the entire channel, the devices prepared by this method have high on-state resistance and high power consumption, and are not very competitive in applications.

[0006] Inspired by this idea, someone started from the perspective of device technology and used the method of digging to reduce the thickness of the barrier layer directly below the gate electrode, reducing the concentration of two-dimensional electron gas here, and preparing the highest threshold voltage. Enhanced devices with about 0.5 volts have relatively low on-state resistance, but the process is very difficult and has almost no repeatability

There are also research groups that develop enhanced devices by preparing a P-type gallium nitride capping layer. Although the gate reverse leakage is very small and the device withstand voltage is high, the threshold voltage is only around 0V.

In 2005, Cai Yong and others at the Hong Kong University of Science and Technology proposed the method of injecting fluorine ions to deplete the two-dimensional electron gas in the channel under the gate, so that the device is in a normally-off state, but the reliability of the device prepared by this method facing great challenges

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