Effect of overdrive voltage on PBTI trapping behavior in GaN MIS-HEMT with LPCVD SiNx gate dielectric**Project supported by the National Key Research and Development Program, China (Grant No. 2017YFB0402800), the Key Research and Development Program of Guangdong Province, China (Grant No. 2019B010128002), the National Natural Science Foundation of China (Grant No. U1601210), and the Natural Science Foundation of Guangdong Province,

Abstract

The effect of high overdrive voltage on the positive bias temperature instability (PBTI) trapping behavior is investigated for GaN metal–insulator–semiconductor high electron mobility transistor (MIS-HEMT) with LPCVD-SiNx gate dielectric. A higher overdrive voltage is more effective to accelerate the electrons trapping process, resulting in a unique trapping behavior, i.e., a larger threshold voltage shift with a weaker time dependence and a weaker temperature dependence. Combining the degradation of electrical parameters with the frequency–conductance measurements, the unique trapping behavior is ascribed to the defect energy profile inside the gate dielectric changing with stress time, new interface/border traps with a broad distribution above the channel Fermi level are introduced by high overdrive voltage.