Characterization of Gate Leakage and Reliability of Normally-OFF GaN MOSFET with LPCVD-SiNx/PEALD-AlN Dual Gate Dielectric and In-Situ H2(15%)/N2(85%) Plasma Pretreatment

Abstract

This paper deeply investigated the gate leakage and dielectric breakdown mechanisms of the Normally-OFF GaN MOSFET with LPCVD-SiNx/PEALD-AlN dual Gate Dielectric and in-situ H2(15%)/N2(85%) plasma pretreatment. The in-situ plasma pretreatment was performed in a PEALD system prior to the PEALD-AlN deposition. Experimental studies showed that the in-situ H2(15%)/N2(85%) plasma pretreatment is effective in improving the quality of the AlN/GaN interface, the LPCVD-SiNx/PEALD-AlN dual Gate Dielectric exhibits not only high breakdown electric field but low leakage current. Experiments have proved dominant mechanism of the leakage current through LPCVD-SiNx/PEALD-AlN Gate Dielectric is identified to be Poole-Frenkel emission at low fields and Fowler-Nordheim tunneling at high fields. Further, gate dielectric time-dependent dielectric breakdown of electric-field-accelerated and temperature-accelerated was investigated.