Fabrication of AlGaN/GaN double‐insulator metal–oxide–semiconductor high‐electron‐mobility transistors using SiO2 and SiN as gate insulators

We report on the fabrication of AlGaN/GaN double‐insulator MOSHEMTs using SiO2 and SiN as the prime gate insulators. Both the dielectrics showed enhanced saturation current density and pinch‐off voltage compared to conventional HEMTs. The SiO2/SiN/AlGaN/GaN MOSHEMTs exhibited a low current collapse and low leakage current compared to SiN MISHEMTs and unpassivated HEMTs. However, the SiN/SiO2/AlGaN/GaN MOSHEMTs exhibited a lower current collapse coupled with moderate leakage current compared to SiO2 MOSHEMTs and unpassivated HEMTs. The comparison of device dc characteristics of double‐insulator MOSHEMTs with single‐insulator MOSHEMTs revealed its superiority in reducing the problem of current collapse and leakage current simultaneously. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)