Defect reduction in laser-crystallized polycrystalline Si films, by heat treatment with 1.3 x 106Pa of H2O vapor, was investigated. The H2O vapor heat treatment at 260C for 6h reduced the spin density in laser-crystallized poly-Si films from 2.0 x 1018 (initial) to 6.5 x 1016/cm3. The activation energy of the reaction for defect reduction was 0.26eV. Photoconductivity under 532nm light illumination at 100mW/cm2 was increased from 2.7 x 10-6 (initial) to 3.3 x 10-5S/cm by heat treatment for 1 h. The O concentration in the Si films was increased by 1.1 x 1019/cm3 by heat treatment, although the H concentration was decreased by 1.4 x 1020/cm3. This suggested that O atoms have an important role in defect state reduction in polycrystalline Si films.

Defect Reduction in Polycrystalline Silicon Thin Films by Heat Treatment with High-Pressure H2O Vapor. T.Sameshima, H.Hayasaka, M.Maki, A.Masuda, T.Matsui, M.Kondo: Japanese Journal of Applied Physics, 2007, 46[3B], 1286-9