Semiconductor device

A semiconductor device comprising:

• a gate electrode layer;
• a gate insulating layer over the gate electrode layer;
• an oxide semiconductor layer over the gate electrode layer with the gate insulating layer therebetween;
• a metal oxide layer comprising an In-M oxide over and in contact with the oxide semiconductor layer;
• and
• a pair of electrode layers in contact with the metal oxide layer,
• wherein the pair of electrode layers comprises one of Cu, Al, Au, and Ag,
• wherein the In-M oxide does not comprise Zn,
• wherein M is one of Ti, Ga, Y, Zr, La, Ce, Nd, and Hf, and
• wherein y/(x+y) is greater than or equal to 0.75 and less than 1 where an atomic ratio of In to M included in the metal oxide layer is In:M=x:y.

A semiconductor device comprising:

• a first gate electrode layer;
• a first gate insulating layer over the first gate electrode layer;
• an oxide semiconductor layer over the first gate electrode layer with the first gate insulating layer therebetween;
• a metal oxide layer comprising an In-M oxide over and in contact with the oxide semiconductor layer;
• a pair of electrode layers in contact with the metal oxide layer;
• a second gate insulating layer over and in contact with the pair of electrode layers;
• and
• a second gate electrode layer over the oxide semiconductor layer with the second gate insulating layer therebetween,
• wherein the pair of electrode layers comprises one of Cu, Al, Au, and Ag,
• wherein the In-M oxide does not comprise Zn,
• wherein M is one of Ti, Ga, Y, Zr, La, Ce, Nd, and Hf, and
• wherein y/(x+y) is greater than or equal to 0.75 and less than 1 where an atomic ratio of In to M included in the metal oxide layer is In:M=x:y, and
• wherein the first gate electrode layer and the second gate electrode layer are electrically connected to each other through an opening in the first gate insulating layer and the second gate insulating layer.