| 摘要 |
PURPOSE:To perform diffusion with good controllability, by subjecting a sub strate to a pretreatment in a vacuum or in vapor phase, for removing an oxide film from the surface of the substrate before forming a thin film serving as a dopant source. CONSTITUTION:An Si substrate 41 which has been wet treated in an ordinary manner is transported to a dry treating chamber 43 via a preliminary exhaust chamber 42. After evacuating the dry treating chamber 43, the substrate 41 is heated so that an oxide film 15 removed from the surface thereof. The sub strate is then transported to another preliminary exhaust chamber 46, where the substrate is cooled gradually. The substrate is then transported to a CVD chamber 47, where a glass layer is formed by reduced pressure CVD by thermal decomposition of tetraethoxysilane and triethoxyarsine. This substrate 41 is heat treated within the atmosphere of N2 so that an arsenic diffused layer is formed on the surface of the substrate 41. In this manner, doping can be performed with desirable controllability even by solid-phase diffusion.
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