The influence of oxygen ambient annealing conditions on the quality of Al/SiO2/n-type 4H-SiC MOS structure

The effect of reoxidation process in O2 on the electrical properties of metal-oxide-semiconductor (MOS) capacitors fabricated on n-type 4H-SiC (0 0 0 1) is investigated. All samples were oxidized in wet oxygen at temperature of 1175 °C. Reoxidation process was carried out on four of the five samples. Samples were annealed at temperature of 700 °C and 800 °C for different process times. The reoxidation process in oxygen improves the quality of the dielectric layer and the interface of Al/SiO2/n-type 4H-SiC MOS structure. The best quality of the SiO2/SiC interface can be achieved for the MOS structure annealed in O2 at higher temperature (800 °C) for longer time. However, higher and more uniformly distributed values of breakdown voltage were obtained for MOS structures reoxidized at temperature of 700 °C.