US Patent 7314784 Thin film transistor and manufacturing method thereof

A channel-length of a TFT can be controlled with higher reproducibility, and a short channel-length of the TFT can be manufactured. Further, a structure of the TFT having an improved current-voltage characteristic is provided. A thin film transistor has a lamination layer where a first conductive film, a first insulating film and a second conductive film are sequentially laminated, a semiconductor film is formed so as to be in contact with the side surface of the lamination layer, and a third conductive film covers the semiconductor film through a second insulating film. The first conductive film and the second conductive film are a source electrode and a drain electrode, a region which is in contact with the first insulating film and the third conductive film is a channel forming region in the semiconductor film, and the third conductive film is a gate electrode.