| 摘要 |
PURPOSE:To decrease OFF current which would flow when a gate electrode is biased negatively, by forming an ohmic contact layer such that a part or all of the layer, contains at least one of carbon, nitrogen and oxygen as a component thereof. CONSTITUTION:On the surface of a glass substrate 1, there are deposited a gate electrode 2, an insulating film 3 and a semiconductor layer 4 successively in that order. An ohmic contact layer 5 is provided thereon except a region where the gate electrode 2 is present. The layer 5 consists of two layers: the lower layer 5a of N<+> a-Si:H, N and the upper layer 5b of N<+> a-Si:H, the upper layer 5b being thicker than the lower layer 5a. The ohmic contact layer 5 will be deteriorated in ohmic properties if it contains excessive N atoms. Preferred concentration of N atoms is 30atomic% or below, particularly 10atomic% or below. A protecting film 6 of SiN is formed on the semiconductor layer 4 not covered with the layers 5a and 5b. A drain electrode 7 and a source electrode 8 both having a layered structure consisting of a Cr layer 20 and an Al layer 21 are provided on the ohmic contact layer 5 with an appropriate gap therebetween. |
