Semiconductor device and method for manufacturing semiconductor device

1. A semiconductor device comprising:

a first insulator;

a first oxide over the first insulator;

a second oxide over the first oxide;

a first conductor and a second conductor apart from each other over the second oxide;

a third oxide over the second oxide, the first conductor, and the second conductor;

a second insulating film over the third oxide; and

a third conductor over the second oxide with the third oxide and the second insulating film positioned therebetween,

wherein the first oxide comprises a first layer and a second layer,

wherein the second layer comprises a metal element and nitrogen, and

wherein the metal element is bonded to nitrogen.

2. The semiconductor device according to claim 1 ,

wherein the second layer is a layer holding a fixed charge.

3. The semiconductor device according to claim 1 ,

wherein a percentage of the number of nitrogen atoms in the second layer is lower than 0.1 atomic %.

4. The semiconductor device according to claim 1 ,

wherein the first layer has a higher oxygen concentration than the second layer, and

wherein the second layer has a higher nitrogen concentration than the first layer.

5. The semiconductor device according to claim 3 ,

wherein the percentage of the number of the nitrogen atoms in the second layer is higher than or equal to 0.02 atomic %.

6. The semiconductor device according to claim 1 ,

wherein the first oxide, the second oxide, and the third oxide comprise In, an element M, and Zn, and

wherein the element M comprises any one of Al, Ga, Y, and Sn.

7. The semiconductor device according to claim 1 ,

wherein the metal element is one selected from In, an element M, and Zn, and

wherein the element M comprises any one of Al, Ga, Y, and Sn.