Investigation and analysis of AlGaN MOS devices with an oxidized layer grown using the photoelectrochemical oxidation method

A photoelectrochemical oxidation method was used to directly oxidize an AlGaN layer as the oxide layer of metal-oxide-semiconductor (MOS) devices. The crystal phases of the oxide films were analyzed by X- ray diffraction (XRD) measurement. The oxide films have a better stability and crystallization after annealing in O-2 ambient at 700 S C for 2 h. The binding configurations of the oxide films were analyzed by X- ray photoelectron spectroscopy ( XPS ). According to the results of XPS, XRD, and secondary ion mass spectrometry ( SIMS ) measurements, the main components of the oxide films consist of Ga2O3 and Al2O3. The average interface state density ( D-it ) between the oxidized AlGaN layer and AlGaN semiconductor is 5.1 x 10(11) cm(-2) eV(- 1). The leakage current of resultant MOS devices with a 45 nm thick oxide layer is 45 nA and 69 pA at 5 and - 15 V, respectively. The breakdown field is 2.2 MV/ cm and 6.6 MV/ cm at breakdown voltage of 10 and - 30 V, respectively. (c) 2007 The Electrochemical Society.