Native oxide GaN as an insulator for MOSFET technology and Cu –Ge metal system for contact to p-GaN has been investigated. CTLM method is used for measurement of specific contact receptivity. Dry thermal oxidation of doped and undoped GaN epilayers is carried out at 8500C for 39, 60, 120, 240 and 600 min. AFM study has been performed to characterize the as grown film and oxidized film of GaN. As grown samples are very smooth and the RMS value of surface roughen is found to lie between 4-10 Angstrons. But oxides films are n very roughness. RMS values of oxides thin films lie between 100 to 110 Angstroms