Semiconductor device and method for manufacturing semiconductor device

A semiconductor device comprising:

• an oxide semiconductor layer;
• a source electrode layer over the oxide semiconductor layer;
• a drain electrode layer over the oxide semiconductor layer;
• a gate insulating layer over the oxide semiconductor layer;
• a gate electrode layer over the gate insulating layer;
• a first insulating film over the gate electrode layer;
• a second insulating film over the first insulating film;
• and
• wherein the first insulating film covers a side surface and an upper surface of the gate electrode layer,
• wherein the first insulating film is in contact with the gate insulating layer,
• wherein the second insulating film covers the side surface and the upper surface of the gate electrode layer,
• wherein the gate insulating layer comprises silicon and oxygen,
• wherein the first insulating film comprises aluminum and oxygen, and
• wherein the second insulating film comprises any one of silicon oxide, silicon nitride, silicon oxynitride and silicon nitride oxide.

A semiconductor device comprising:

• a first transistor comprising a silicon semiconductor layer;
• a first insulating layer over the first transistor;
• an oxide semiconductor layer over the first insulating layer;
• a source electrode layer over the oxide semiconductor layer;
• a drain electrode layer over the oxide semiconductor layer;
• a gate insulating layer over the oxide semiconductor layer;
• a gate electrode layer over the gate insulating layer;
• a first insulating film over the gate electrode layer;
• and
• a second insulating film over the first insulating layer;
• wherein the first insulating film covers a side surface and an upper surface of the gate electrode layer,
• wherein the first insulating film is in contact with the gate insulating layer,
• wherein the second insulating film covers the side surface and the upper surface of the gate electrode layer,
• wherein the gate insulating layer comprises silicon and oxygen,
• wherein the first insulating film comprises aluminum and oxygen,
• wherein the second insulating film comprises any one of silicon oxide, silicon nitride, silicon oxynitride and silicon nitride oxide, and
• wherein one of the source electrode layer and the drain electrode layer is electrically connected to the first transistor.