Studies on High-Voltage GaN-on-Si MIS-HEMTs Using LPCVD Si3N4 as Gate Dielectric and Passivation Layer

This paper investigates the performance of AlGaN/gallium nitride (GaN) MIS high electron mobility transistors (MIS-HEMTs). The gate dielectric layer and the surface passivation layer are formed by the low-pressure chemical vapor deposition (LPCVD) Si3N4. The LPCVD-Si3N4 MIS-HEMTs exhibit a high breakdown voltage (BV) of 1162 V at I-DS = 1 mu A/mm, a low OFF-state leakage of 7.7 x 10(-12) A/mm, and an excellent ON/OFF-current ratio of similar to 10(11). Compared with the static ON-resistance of 2.88 m Omega . cm(2), the dynamic ON-resistance after high OFF-state drain bias stress at 600 V only increases to 4.89 m Omega . cm(2). The power device figure of merit = BV2/R-ON.sp is calculated to be 469 MW . cm(-2). The LPCVD-Si3N4/GaN interface state density is in the range of (1.4-5.3) x 10(13) eV(-1) cm(-2) extracted by the conventional conductance method. Finally, the gate insulator degradation of GaN-based MIS-HEMTs is analyzed by time-dependent dielectric breakdown test. The lifetime is extrapolated to 0.01% of failures after ten years at 300 K by fitting the data with a power law to a gate voltage of 10.1 V.