SiO2 insulating layers were deposited onto 4H-SiC substrates by a photochemical vapor deposition (photo-CVD) technique. It was found that the SiO2 growth rate increases linearly with total SiH4/O-2 density for a fixed ratio of SiH4 and O-2 partial pressure, due-to the increasing densities of SiH2 and excited O atoms. It was also found that the interface state density, D-it, is equal to 3.27 x 10(12), 3.16 x 10(12), and 5.66 x 10(11) cm(-2) eV(-1) for photo-CVD SiO2 layers prepared at 150, 300, and 500 degreesC, respectively. Furthermore, it was found that the leakage current was only 4.15 x 10(-8) A/cm(2) with an applied field of 4 MV/cm for the 500 degreesC photo-CVD grown Al/SiO2/4H-SiC metal-insulator-semiconductor capacitor. (C) 2003 American Vacuum, Society.