Comparative Studies on AlGaN/GaN MOS-HEMTs with Stacked La₂O₃/Al₂O₃Dielectric Structures

Abstract

This work provides comparative studies of AlGaN/GaN MOS-HEMT with the devised stacked La2O3/Al2O3 dielectric structure with respect to a conventional Schottky-gate HEMT and a reference La2O3-dielectric MOS-HEMT, which were all fabricated on the identical epitaxial layers. The La2O3/Al2O3 stacked dielectrics are formed by using RF magnetron sputter/H2O2 oxidization. Transmission electron microscopy (TEM), capacitance-voltage (C-V) measurement with different frequency, and low-frequency noise (LFN) analysis were used to study the interface and oxide quality. Comprehensive studies on electrical and thermal stability characteristics have been performed. Improved transconductance gain (gm), current drive, breakdown, and thermal stability at 300–480 K are achieved in the present MOS-HEMT design.