Defect concentration in polycrystalline silicon (poly-Si) films formed by thermal plasma jet (TPJ) annealing and excimer laser annealing (ELA) was investigated on the basis of the electrical property and spin density (Ns). Phosphorus-doped Si films with an average concentration of 4.3 x 1017/cm3 and crystallized by TPJ annealing exhibited electrical conductivity (σ) values of 2.0 x 10-3 to 7.8 x 10-2S/cm, whereas ELA Si films exhibited much lower σ values of (1.6–4.5) x 10-6S/cm; regardless of the irradiated laser energy density. The Ns values in TPJ annealed Si films were (2.3–4.5) x 1017/cm3, which were roughly an order of magnitude lower than those of ELA films. These results indicated that dangling bonds in crystallized films were the predominant traps and they strongly governed the electrical properties. TPJ crystallization offered the possibility of fabricating poly-Si films with a low defect concentration; presumably owing to the much lower cooling rate (∼105K/s) during crystalline growth than that of ELA (∼1010K/s). By treating TPJ annealed films with hydrogen plasma for 600s at 250C, a defect density as low as 5.0 x 1016/cm3 was achieved.

Formation of Low-Defect-Concentration Polycrystalline Silicon Films by Thermal Plasma Jet Crystallization Technique. T.Yorimoto, S.Higashi, H.Kaku, T.Okada, H.Murakami, S.Miyazaki, T.Matsui, A.Masuda, M.Kondo: Japanese Journal of Applied Physics, 2008, 47, 6949-52