Comparisons Of Sin Passivation Film Deposited By Pe-Cvd And T-Cvd Method For Algan/Gan Hemts On Sic Substrate

Current collapse phenomenon is a well known obstacle in the AlGaN/GaN HEMTs. In order to improve the surface stability of HEMTs. we have investigated the SiN passivation film deposited by T-CVD. and we found that it improves both gate leakage current and current collapse phenomenon [1]. Moreover, we compared the T-CVD and PE-CVD passivation films, on high electric field DC and RF characteristics. We found that T-CVD SiN passivation film improves BVds-off by 30% because of the reduction of gate leakage current. It also improved eta(d) in the output power characteristics by load-pull measurement, which indicates the decrease of the current collapse phenomenon. Also we fabricated a multi-fingered SOW-class AlGaN/GaN HEMT with T-CVD SiN passivation film and achieved 61.2% of high drain efficiency at frequency of 2.14 GHz. which was 3.6 points higher than that with PE-CVD SiN passivation film.