Analysis of Chemical Reactions for Control of Si-Network-from Amorphous to Single Crystal-

点击翻译按钮获取中文摘要

A systematic study was performed to realize the control of chemical reactions at the growing surface of Si-network for the aim of fabrication of Si thin films at low temperature as low as 300ﾟC with the structures, viz., amorphous, poly-(or muc-)Si and epi-Si by adopting non-equilibrium processing. An ellipsometry together with simulation by Effective Medium Approximation was employed as the in situ observation of the surface.A novel technique termed "Chemical Annealing" was proposed, where the deposition of very thin film of 10 A thick by RF glow of silane was alternately repeated with the treatment with atomic hydrogen generated by muW plasma. a-Si : H thin films with more rigid and stable network were successfully made by this technique due to promotion of the structural relaxation at the growing surface. In addition, we succeeded to fabricate highly stabilized a-Si : H for light soaking from SiCl_2H_2 by means of ECR hydrogen plasma. Strong chemical interaction between bydrogen and chlorine at the surface was responsible for the relaxation.Radicals given by SiFnHm (n+m(〕SY.ltoreq.〔)3) were promising precursors to fabricate Si-network with ordered structures. Epi-Si was grown on c-Si(100) from the fluorinated precursors at 300ﾟC or lower. In addition, high quality poly-Si films were grown on glass substrate using this precursors by repeating alternately the deposition of thin layr of 100 A thick and the treatment of the surface with flow of atomic hydrogen. (Leyer-by-Layr Technique) The phase transition from amorphous to crystalline was induced by impingement of hydrogen, which is considered to be responsible for the grain growth. High qualities in the electric and optical properties were established.