TiO2 insertion layer deposited before passivation to reduce etch damage on AlGaN/GaN HEMT

Gamma-gate has been used to increase the breakdown voltage of radio frequency (RF) devices, and the damage caused by gate pin etching has been studied. In this study, a TiO2 layer, acting as a protective layer, was inserted between the AlGaN barrier layer and SiN passivation layer. The AlGaN/GaN high-electron-mobility transistor (HEMT) with TiO2 had no kink effect in its output characteristic, and at high gate voltages, it demonstrated a higher transconductance than the HEMT without TiO2. The HEMT without TiO2 exhibited a more prominent saturation tendency for drain current. Additionally, the C-V test data show that the trap state density of the AlGaN/GaN interface of an AlGaN/GaN HEMT with TiO2 decreased compared with a HEMT without TiO2. DC and C-V test results show that the TiO2 layer can effectively reduce the etching damage of the material under the gate. (C) 2022 The Japan Society of Applied Physics

Automated summary

In this study, a protective TiO2 layer was inserted to reduce the damage caused by gate pin etching in radio frequency devices. It was found that the HEMT with TiO2 showed improved output characteristics and transconductance, and a lower trap state density at the AlGaN/GaN interface with TiO2.