Thin-film transistor and method for the production thereof

摘要

A thin-film transistor according to the invention is characterised by the following: - a substrate (71); - a gate pole (73) which is formed in the central part of the substrate; - a semiconductor layer (75) which is formed such that it surrounds the gate pole on the substrate; - a side-wall spacer (77) which is formed on the side of the gate pole on the semiconductor layer; and - impurity (foreign-matter) regions (82, 83) of high density, which are formed in the semiconductor layer on both sides of the gate pole, the impurity density dropping gradually under the side-wall spacer towards the gate pole. A method according to the invention for producing a TFT is characterised by the following steps: - production of a gate pole in the central part of a substrate; - production of a gate-insulating film on a semiconductor layer over the entire surface area of the substrate; - formation of a side-wall spacer only on one side of the gate pole on the semiconductor layer; and - formation of impurity regions of high density in the semiconductor layer on both sides of the gate by ion injection of impurity ions into the semiconductor layer. <IMAGE>