Comb-type gate structure HEMT radio frequency device and preparation method thereof

Abstract

The invention relates to a comb-type gate structure HEMT radio frequency device and a preparation method thereof. The comb-type gate structure HEMT radio frequency device comprises an AlN buffer layer, an AlGaN buffer layer with a gradually-changed Al component, a GaN channel layer, an AlGaN layer, a source electrode, a drain electrode and a comb-type gate located between the source electrode and the drain electrode; the comb-type gate comprises a gate head and a gate foot; the gate foot comprises a first sub-gate foot, a second sub-gate foot and a third sub-gate foot; the first sub-gate foot, the second sub-gate foot and the third sub-gate foot are sequentially arranged on the surface of the AlGaN layer at intervals in the direction from the source electrode to the drain electrode, and an air gap is formed between every two adjacent sub-gate feet. Due to the arrangement of the comb-type gate structure, the gate resistance is reduced, the noise coefficient is reduced, and meanwhile, the gain is improved; a passivation layer medium is not arranged between the gate head and the gate foot, and air is arranged in a gap between the adjacent gate feet, so that the parasitic capacitance of the gate is reduced, and the cut-off frequency is improved; and the three gate feet are arranged at intervals, so that the control of the gate to a channel is enhanced, the transconductance is more stable along with the change of gate-source voltage, and the linearity is obviously improved.

Description

technical field [0001] The invention relates to the field of high electron mobility transistors, in particular to a comb-shaped gate structure HEMT radio frequency device and a preparation method thereof. Background technique [0002] High Electron Mobility Transistor (HEMT) is a field effect transistor, which is a heterojunction formed by two materials with different band gaps, providing a channel for carriers, and the formed two-dimensional electron gas has high mobility. , a higher output power can be obtained. Compared with Si-based laterally diffused metal oxide semiconductors and GaAs, GaN HEMT radio frequency devices at the base station can more effectively meet the high power, high communication frequency band and high efficiency requirements of 5G, so the research on the radio frequency performance of GaN HEMT has received many focus on. [0003] The RF characteristic parameters of GaN HEMT devices mainly include cut-off frequency (f T ), the highest oscillation ...

AI Technical Summary

Problems solved by technology

The method of scaling down the device improves the frequency characteristics, but deteriorates the breakdown voltage of the device

Structures such as field plates and T-shaped gates improve the frequency characteristics, but deteriorate the noise performance of the device, resulting in unstable operation

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