Semiconductor device and process for formation thereof

摘要

A recess is formed (dug) into the surface of a substrate to form a gate channel in the recess, so that a monocrystalline source/drain region can be formed at a level higher than that of the channel. The process includes the steps of: (a) forming an insulating layer and an oxidation preventing layer on a semiconductor substrate, and removing the oxidation preventing layer of a channel region of the transistor by an etching process; (b) forming an oxide layer on the channel region of the transistor by thermally oxidizing the semiconductor substrate, removing the oxidation preventing layer, and carrying out a first ion implantation on the whole surface; (c) removing the oxide layer, and forming the channel of the transistor in the form of a recess so as for the recess to be positioned lower than the surface of the substrate; (d) forming a gate electrode in the recess; and (e) carrying out a second ion implantation on the whole surface, and carrying out a heat treatment to form a source/drain region.