Process for producing semiconductor device

摘要

A process for producing a semiconductor device for an integrated circuit is disclosed. A patterned structure made of first polycrystalline silicon and a first thermal oxide film is formed on an underlayer or foundation. A protrusion or raised portion is formed by using the patterned structure as a mask. A first insulating region is formed around the protrusion. After removing the first thermal oxide film an remaining portion of the patterned structure is thermally oxidized to obtain second thermal oxide film while the peripheral area of the surface of the protrusion is exposed. A second polycrystalline silicon pattern layer with a high impurity concentration is formed so as to contact with the exposed surface of the protrusion and with sideface of the second thermal oxide film, and to extend onto the first insulating layer. The pattern layer is subject to thermal treatment to form a control electrode with a third thermal oxide film thereon and to form a low resistance region for a part of a control region in the protrusion. Thus, the portion of the control electrode contacting with the second thermal oxide film is formed in self-alignment manner. At later stages, a remaining part of the control electrode region and a first principal electrode region are sequentially formed in a self-alignment manner in the protrusion while the residual are of the protrusion serves as a second electrode region.