Patent ID: 7952095

Claim:
A display device, comprising: a first thin film transistor and a second thin film transistor on a substrate; wherein the first thin film transistor includes: a first gate electrode covered by a silicon nitride film, a silicon oxide film selectively formed on the silicon nitride film, a first semiconductor layer formed at least on an upper surface of the silicon oxide film and formed of pseudo single crystal silicon or polycrystalline silicon, a second semiconductor layer formed at least on an upper surface of the first semiconductor layer and formed of amorphous silicon, and a first drain electrode an a first source electrode which are formed on an upper surface of the second semiconductor layer by way of a first contact layer; wherein the second thin film transistor includes: a second gate electrode covered by the silicon nitride film, a third semiconductor layer formed at least on and in physical contact with an upper surface of the silicon nitride film and formed of amorphous silicon, and a second drain electrode and a second source electrode which are formed on an upper surface of the third semiconductor layer by way of a second contact layer; wherein the second gate electrode of the second thin film transistor is formed at the same layer as the first gate electrode of the first film transistor; wherein the third semiconductor layer of the second thin film transistor is the same layer as the second semiconductor layer of the first thin film transistor; wherein the second contact layer of the second thin film transistor is the same layer as the first contact layer of the first thin film transistor; and wherein a peripheral-side wall surface of first semiconductor layer is contiguously constituted with a peripheral-side wall surface of the silicon oxide film below the first semiconductor layer without a stepped portion.