High-Pressure Water-Vapor Annealing for Enhancement of a-Si:H Film Passivation of Silicon Surface

We investigate the effect of amorphous hydrogenated silicon (a-Si:H) films passivated on silicon surfaces based on high-pressure water-vapor annealing (HWA). The effective carrier lifetime of samples reaches the maximum value after 210°C, 90 min HWA. Capacitance-voltage measurement reveals that the HWA not only greatly reduces the density of interface states (D_it), but also decreases the fixed charges (Q_fixed) mainly caused by bulk defects. The change of hydrogen and oxygen in the film is measured by a spectroscopic ellipsometer and a Fourier-transform infrared (FTIR) spectrometer. All these results show that HWA is a useful method to improve the passivation effect of a-Si:H films deposited on silicon surfaces.