On conduction mechanisms through SiN/AlGaN based gate dielectric and assessment of intrinsic reliability

The first section of this article focuses on the investigations of the gate leakage conduction mechanisms under forward and reverse bias conditions using temperature dependent Jg-Eg characteristics on a Silicon Nitride (SiN)/AlGaN based Metal-Insulator-Semiconductor (MIS) structure. TCAD study under forward bias conduction show majority of the voltage drop on the SiN layer only. The model fitting the electrical characteristics was observed to be Poole-Frenkel (PF) emission. Under reverse bias condition, the entire voltage drop occurs on the entire SiN/AlGaN/GaN. The conduction mechanism responsible for the leakage was found to be Fowler-Nordheim (FN) tunneling along with a thermionic emission component. Second section of this article focuses on the Time Dependent Dielectric Breakdown (TDDB) measurements and lifetime extrapolation of the SiN/AlGaN based di-electric stack. TDDB measurements were done under constant field stress for different temperatures. Normalization of the data exhibited only field accelerated degradation with no influence from the temperature.