Semiconductor device, display device including the semiconductor device, display module including the display device, and electronic device including the semiconductor device, the display device, and the display module
To provide a semiconductor device including a planar transistor having an oxide semiconductor and a capacitor. In a semiconductor device, a transistor includes an oxide semiconductor film, a gate insulating film over the oxide semiconductor film, a gate electrode over the gate insulating film, a second insulating film over the gate electrode, a third insulating film over the second insulating film, and a source and a drain electrodes over the third insulating film; the source and the drain electrodes are electrically connected to the oxide semiconductor film; a capacitor includes a first and a second conductive films and the second insulating film; the first conductive film and the gate electrode are provided over the same surface; the second conductive film and the source and the drain electrodes are provided over the same surface; and the second insulting film is provided between the first and the second conductive films.
1. A transistor comprising:
an island-shaped oxide semiconductor film;
a single-layer gate insulating film over the island-shaped oxide semiconductor film; and
a gate electrode over the single-layer gate insulating film,
wherein, in a cross-sectional view parallel to a channel length direction of the transistor, an edge of the single-layer gate insulating film is located on a top surface of the island-shaped oxide semiconductor film,
wherein a first insulating film comprising a region in contact with a side surface of the gate electrode, a region in contact with a top surface of the single-layer gate insulating film, and a region in contact with the top surface of the island-shaped oxide semiconductor film, is provided,
wherein the top surface of the single-layer gate insulating film comprises a region projecting from the gate electrode,
wherein the transistor is a top-gate transistor,
wherein, in the cross-sectional view, the island-shaped oxide semiconductor film comprises a first region overlapping with the single-layer gate insulating film and a second region not overlapping with the single-layer gate insulating film, the second region having a smaller thickness than the first region, and
wherein at least one of a source electrode and a drain electrode comprises a region in contact with a top surface of the second region.
2. The transistor according to claim 1 , wherein the island-shaped oxide semiconductor film comprises In, Ga, and Zn.
3. The transistor according to claim 1 , wherein the island-shaped oxide semiconductor film comprises a crystal part.
4. The transistor according to claim 1 , further comprising:
a conductive layer under the island-shaped oxide semiconductor film,
wherein the conductive layer comprises a region overlapping with the island-shaped oxide semiconductor film with a second insulating film therebetween.
5. The transistor according to claim 1 ,
wherein the island-shaped oxide semiconductor film further comprises a third region in contact with the first insulating film,
wherein the second region has a higher conductivity than the first region, and
wherein the third region has a higher conductivity than the first region.