Characterization of Recessed-Gate AlGaN/GaN HEMTs as a Function of Etch Depth

摘要

Recessed-gate high-electron-mobility transistors (HEMTs) were fabricated using a Cl_(2)-based plasma etch to study device performance as a function of recess depth. Devices were fabricated with recess depths varying from 0 nm to 25 nm on a standard HEMT structure using a controllable, low-power etch recipe. It is shown that the threshold voltage approached zero as the recess approached the AlGaN/GaN heterojunction. At the same time, mobility decreased an order of magnitude over the etch range studied, and sheet carrier density also decreased. In addition to direct-current (DC) I-V and Hall measurements, electroluminescence was also used to characterize plasma damage in these devices.