Wet thermal oxidation for GaAs, GaN and Metal/GaN device applications

Thermal wet oxidation of gallium arsenide GaAs (wafers) and gallium nitride GaN (layers from metalorganic vapor phase epitaxy MOVPE and hydride vapor phase epitaxy HVPE) was carried out in N2 as a main gas and H2O as an oxidizing agent. Materials parameters and surface morphology were studied by means x-ray diffraction, ellipsometry, photoreflectance PR, micro Raman spectroscopy, optical microscopy and atomic force microscopy AFM. The lack of materials parameters or their wide range, especially refractive index, dielectric constant and their dependence of oxide´s composition and structure constituted some problems during measurements. GaAs oxidation was more difficult as GaN oxidation, especially GaN from HVPE.