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 O2 ambient at 700°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 Ga2 O3 and Al2 O3. The average interface state density (Dit) between the oxidized AlGaN layer and AlGaN semiconductor is 5.1× 1011 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 MVcm and 6.6 MVcm at breakdown voltage of 10 and -30 V, respectively.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry