Semiconductor device and method for manufacturing semiconductor device

A semiconductor device comprising:

• a transistor comprising:
• a gate electrode over a substrate;
• a first insulating layer over the gate electrode, the first insulating layer comprising hafnium oxide;
• a second insulating layer over the first insulating layer, the second insulating layer comprising silicon and oxygen;
• an oxide semiconductor layer over and in contact with the second insulating layer, the oxide semiconductor layer comprising a channel formation region, wherein the channel formation region comprises indium and oxygen;
• and
• a source electrode and a drain electrode in contact with the oxide semiconductor layer;
• and
• a third insulating layer over the oxide semiconductor layer,
• wherein the first insulating layer has higher relative permittivity than the second insulating layer.

A semiconductor device comprising:

• a transistor comprising:
• a gate electrode over a substrate;
• a first insulating layer over the gate electrode, the first insulating layer comprising hafnium oxide;
• a second insulating layer over the first insulating layer, the second insulating layer comprising SiOx (x>2);
• an oxide semiconductor layer over and in contact with the second insulating layer, the oxide semiconductor layer comprising a channel formation region, wherein the channel formation region comprises indium and oxygen;
• and
• a source electrode and a drain electrode in contact with the oxide semiconductor layer;
• and
• a third insulating layer over the oxide semiconductor layer,
• wherein the first insulating layer has higher relative permittivity than the second insulating layer.

A semiconductor device comprising:

• a transistor comprising:
• a first gate electrode over a substrate;
• a first insulating layer over the first gate electrode, the first insulating layer comprising hafnium oxide;
• a second insulating layer over the first insulating layer, the second insulating layer comprising silicon and oxygen;
• an oxide semiconductor layer over and in contact with the second insulating layer, the oxide semiconductor layer comprising a channel formation region, wherein the channel formation region comprises indium and oxygen;
• and
• a source electrode and a drain electrode in contact with the oxide semiconductor layer;
• a third insulating layer over the oxide semiconductor layer;
• and
• a second gate electrode over the oxide semiconductor layer with the second insulating layer interposed therebetween, wherein the first gate electrode and the second gate electrode overlap with each other,
• wherein the first insulating layer has higher relative permittivity than the second insulating layer.