Effect of substrate temperature and post-deposition annealing on intrinsic a-SiOx:H film for n-Cz-Si wafer passivation

Abstract

In order to make sure the co-operation of substrate temperatures and post-deposition annealing on the structure and performance of the a-SiOx:H for n-Cz-Si wafer passivation, three series a-SiOx:H films bifacial-deposited on n-Cz-Si wafers were made. In which, the first series was deposited at room temperature and post-deposition annealing with different temperature; the second series was deposited with different substrate temperature and without post-annealing; and the third series was deposited with different substrate temperature and post-annealed at the optimized 275 °C. Effective lifetime of the samples was tested by QSSPC method, and the imaginary part of dielectric constant (e 2) and film properties of the films were analyzed by Spectroscopic Ellipsometry and Fourier Transform Infrared Spectroscopy. It is concluded that (1) the structure and passivation effect of a-SiOx:H films on n-Cz-Si wafer are sensitive to the substrate temperature and post-deposition annealing, and the optimum scheme is depositing the film at 100 °C and post-annealing the wafer at 275 °C; (2) the microstructure parameter R * of the a-SiOx:H is ~0.67 for the samples with the optimum passivation effect.