Stepped ohmic structure of AlGaN/GaN HEMT with lower off-state leakage current

Abstract

Abstract Utilizing the TCAD-ATLAS platform, we performed accurate fitting of the electrical characteristics of GaN HEMT devices, achieving a fitting error of less than 5%. Building upon this parameter fitting, we introduced a stepped ohmic structure and compared it with the conventional rectangular structure. The findings highlight the significant impact of the ohmic structure on the off-state drain leakage current of the device. Through the implementation of the stepped ohmic structure, a remarkable reduction in the off-state leakage current was achieved. Specifically, the off-state leakage current decreased by three orders of magnitude, declining from 10−5 mA/mm to 10−8 mA/mm. Importantly, this improvement in leakage current was accomplished without adversely affecting the device’s output characteristics. These results underscore the effectiveness of the stepped ohmic structure in enhancing the overall performance of GaN HEMT devices.