| 摘要 |
PROBLEM TO BE SOLVED: To simultaneously solve two problems called the depletion of a gate electrode and the penetration of impurities into a semiconductor substrate in a semiconductor device having a MOS structure. SOLUTION: The manufacturing method of a semiconductor device comprises a process where a gate insulating film 2 is formed on the surface of a silicon substrate 1 and a process that after hydroxyl groups 3 are adsorbed on the surface of the film 2, a polycrystalline silicon film 4, which is a polycrystalline semiconductor film is formed on the film 2 by a chemical phase growth method. In this way, the lateral mean crystal grain diameters, which are sectioned by crystal grain boundaries 5, in the polycrystalline semiconductor film are controlled to be small. Moreover, in this MIS structure, when the diffusion constant of impurities in the crystal grains in the polycrystalline semiconductor film, the diffusion coefficient of impurities in the film 2 and a heat treatment time are respectively assumed to be Dc, Dox and ta, the film 2 and the polycrystalline semiconductor film are formed, so that the film thickness of the film 2 exceeds 2 (Do×ta)1/2 and the lateral mean crystal grain diameter in the polycrystalline semiconductor film will not exceed 4 (Dc×ta)1/2.
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