Self-alignment grid-based GaN ultrahigh-frequency device and fabrication method thereof

Abstract

The invention discloses a high-gain and ultrahigh-frequency GaN device and a fabrication method thereof. By the high-gain and ultrahigh-frequency GaN device, the problem of low frequency, gain and power conversion efficiency of an existing similar device is mainly solved. The device comprises a substrate (1), an AlN nucleating layer (2), a GaN buffer layer (3), an AlN insertion layer (4), an AlGaN barrier layer (5) and a passivation layer (7) from bottom to top, wherein a source electrode (8) and a drain electrode (9) are arranged at two ends of the GaN buffer layer, a metal interconnection layer (11) is arranged on the source electrode and the drain electrode, a self-alignment stepped dual-T-shaped electrode (10) is arranged on the AlGaN barrier layer, a groove is formed in a grid pin (101) of the grid electrode, a grid dielectric layer (6) is arranged above the groove, and the passivation layer is arranged on a surface of the barrier layer at two sides of the grid electrode pin. By the high-gain and ultrahigh-frequency GaN device, the grid electric leakage and the parasitic capacitance are reduced, the current collapse is suppressed, the power conversion efficiency and the frequency and gain characteristic of the device are improved, and the high-gain and ultrahigh-frequency GaN device can be used as a high-gain and ultrahigh-frequency device.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, in particular to a high-gain ultra-high frequency device, which can be used in communication, satellite navigation, radar system and base station system. Background technique [0002] With the advancement of science and technology, the existing first and second generation semiconductor devices can no longer meet the needs of higher frequency, higher power, and lower power consumption in the field of communication technology development. The new wide bandgap compound semiconductor material GaN, obtained Thanks to its wide bandgap, high breakdown electric field, and high thermal conductivity, corrosion resistance, radiation resistance and other excellent characteristics that silicon-based semiconductor materials do not have, it can greatly meet the requirements of today's communication technology. The development needs of the device have greatly improved the performance of the device, maki...

AI Technical Summary

Problems solved by technology

[0009] First, when the device etches grooves under the gate, due to the instability of common methods, it often leads to the expansion of the sidewall of the etched groove and the etching accuracy is difficult to control, which reduces the confinement of the gate feet, reduces the output current, and affects Device gain, resulting in poor uniformity of on-chip devices;

[0010] The second is that the conventional T-shaped gate and the etching of the groove under the gate belong to two process steps, which puts forward high requirements on the alignment accuracy of the two steps, and the yield of the preparation method is not high;

[0011] The third is to deposit SiO under the device gate 2 After the gate dielectric, the parasitic capacitance of the MIS structure will not only degrade the frequency characteristics of the device, but also reduce the size of the SiO 2 Thinning will make the gate control capability and device withstand voltage capability weaker, and the leakage will be more serious;

[0012] The fourth is the passivation process introduced on the surface of the device. The thickness of the passivation layer is not easy to control. If it is too thick, excessive parasitic capacitance will be introduced, resulting in the degradation of the frequency characteristics of the device.

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