Semiconductor device and method for manufacturing semiconductor device
An object is to reduce the manufacturing cost of a semiconductor device. An object is to improve the aperture ratio of a semiconductor device. An object is to make a display portion of a semiconductor device display a higher-definition image. An object is to provide a semiconductor device which can be operated at high speed. The semiconductor device includes a driver circuit portion and a display portion over one substrate. The driver circuit portion includes: a driver circuit TFT in which source and drain electrodes are formed using a metal and a channel layer is formed using an oxide semiconductor; and a driver circuit wiring formed using a metal. The display portion includes: a pixel TFT in which source and drain electrodes are formed using an oxide conductor and a semiconductor layer is formed using an oxide semiconductor; and a display wiring formed using an oxide conductor.
1. A semiconductor device comprising a pixel portion and a driver circuit portion each including a transistor, the transistor comprising:
a first conductive layer;
a first insulating layer over the first conductive layer;
an oxide semiconductor layer over the first insulating layer;
a second insulating layer over the oxide semiconductor layer;
a second conductive layer and a third conductive layer over the second insulating layer;
a third insulating layer over the second conductive layer and the third conductive layer; and
a fourth conductive layer over the third insulating layer,
wherein a first length of the second insulating layer is smaller than a first length of the first conductive layer in a channel length direction, and
wherein a second length of the second insulating layer is smaller than a second length of the first conductive layer in a channel width direction.
2. The semiconductor device according to claim 1 , wherein the first conductive layer comprises copper.
3. The semiconductor device according to claim 1 , wherein the oxide semiconductor layer comprises indium, gallium, and zinc.
4. The semiconductor device according to claim 1 , wherein the fourth conductive layer comprises zinc.
5. The semiconductor device according to claim 1 , wherein the fourth conductive layer has a light-transmitting property.
6. The semiconductor device according to claim 1 , wherein the fourth conductive layer of the pixel portion is a pixel electrode.
7. The semiconductor device according to claim 1 , wherein the second insulating layer comprises silicon oxynitride.
8. The semiconductor device according to claim 1 , wherein the fourth conductive layer of the driver circuit portion is electrically connected to the first conductive layer of the driver circuit portion.
9. The semiconductor device according to claim 1 , wherein the first conductive layer and the fourth conductive layer of the driver circuit portion are supplied with a same potential.
10. The semiconductor device according to claim 1 , wherein the pixel portion comprises a capacitor having a light-transmitting property.
11. The semiconductor device according to claim 1 ,
wherein the oxide semiconductor layer comprises a region in contact with the second insulating layer, and
wherein a carrier concentration of the region is less than 1 ×10 17 /cm 3 .