Patent ID: 8785928

Claim:
A semiconductor device comprising: a pixel portion including a plurality of pixels; and a source signal line driver circuit portion including a first circuit and a second circuit, wherein the first circuit is configured to control timing for sampling video signals, wherein the second circuit is configured to sample the video signals in accordance with the timing and is configured to input sampled video signals to the plurality of pixels, wherein the second circuit includes a first transistor and a second transistor, the first transistor comprising a first oxide semiconductor film and a second oxide semiconductor film which are stacked with each other, wherein the first oxide semiconductor film comprises indium and a Group 13 element other than the indium and has a composition where an atomic percent of the indium is greater than an atomic percent of the Group 13 element other than the indium, wherein the second oxide semiconductor film comprises indium and a Group 13 element other than the indium and has a composition where an atomic percent of the indium is less than or equal to an atomic percent of the Group 13 element other than the indium, wherein the first circuit and the second circuit are electrically connected to each other by a wiring, and wherein the wiring is electrically connected to a gate of the first transistor and a gate of the second transistor.