Semiconductor device and active matrix substrate using semiconductor device

A semiconductor device comprising:

• an insulating substrate including a pixel area and a peripheral circuit area around the pixel area;
• a first insulating layer which is provided on the insulating substrate and includes at least nitrogen.;
• a second insulating layer provided on the first insulating layer;
• a first thin-film transistor which is provided on the second insulating layer in the pixel area and comprises a first oxide semiconductor layer;
• and
• a second thin-film transistor which is provided on the second insulating layer in the peripheral circuit area and comprises a second oxide semiconductor layer, wherein
• the first insulating layer in the pixel area is thicker than that in the peripheral circuit area.

A semiconductor device comprising:

• an insulating substrate;
• a first insulating layer which is provided on the insulating substrate and includes at least nitrogen;
• a thin-film transistor which is provided above the first insulating layer and comprises a first oxide semiconductor layer;
• a capacitor which is provided above the first insulating layer and comprises a second oxide semiconductor layer;
• and
• a second insulating layer at least provided between the first insulating layer and the first oxide semiconductor layer of the thin-film transistor.

A semiconductor device comprising:

• an insulating substrate;
• a first insulating layer which is provided on the insulating substrate and includes at least nitrogen;
• a second insulating layer provided on the first insulating layer;
• a thin-film transistor which is provided on the second insulating layer and comprises a first oxide semiconductor layer;
• and
• a capacitor which is provided on the second insulating layer and comprises a second oxide semiconductor layer, wherein
• the first insulating layer under the first oxide semiconductor layer is thinner than that under the second oxide semiconductor layer.