| 摘要 |
PURPOSE:To obtain an impurity diffusion layer wherein the diffusion depth is uniform and the transversal spread is small, by forming apertures having a form wherein a fine pattern is arranged on the oxide film for a mask of a region in which an impurity diffusion layer is to be formed, spreading thereon a coating insulating film, and forming an impurity diffusion layer by thermal diffusion. CONSTITUTION:On an Si substrate 1, an oxide film 2 is formed by a thermal oxidation method. On the oxide film 2 in a region where an impurity diffusion layer 4a is to be formed, fine appertures 21 are formed so as to distribute densely and uniformly. A coating insulative film 3 in which boron, antimon, phoshorus, arsenic, etc., are contained as an impurity diffusion source is spread and formed on the upper whole surface of the oxide film 2 including the apertures 21. Then, by heat-treating, impurity elements are diffused from the coating insulating film 3 containing impurity, and an impurity diffusion layer 4a is formed. Finally, the coating insulating film 3 coating impurity and the oxide film 2 which become unnecessary are eliminated by etching. Thereby, an impurity diffusion layer suitable to fine structure whose diffusion depth is uniform can be formed.
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