GaAs MOS capacitors with photo-CVD SiO2 insulator layers

SiO2 films were successfully deposited onto n-GaAs substrates by photo-chemical vapor deposition (photo-CVD) using a deuterium (D2) lamp as the excitation source. With a 1 MV/cm applied electric field, it was found that the SiO2 films leakage current densities were 1.74 × 10−6 and 1.97 × 10−7 A/cm2, respectively, for the capacitors with as-deposited and 400 °C annealed insulator layers. The interface state densities, Dit, were also found to be small for the fabricated Al/photo-CVD-SiO2/GaAs metal-oxide-semiconductor field effect transistors (MOSFETs) capacitors.