A two step gate dielectric deposition technique on GaN, viz. thermal oxidation of Low Pressure Chemical Vapor Deposited (LPCVD) silicon is reported. Current-Voltage (I-V) and Capacitance-Voltage (C-V) characterization of the Metal Insulator Semiconductor (MIS) capacitors are carried out to assess the interface properties. MIS devices with thermal oxide show improved I-V characteristics compared to those with Plasma Enhanced Chemical Vapor Deposited (PECVD) SiO2. However, Si deposition and oxidation schedule has to be carefully optimized to achieve high quality SiO2 on GaN. ©2009 IEEE.