Patent ID: 8901656

Claim:
A semiconductor wafer comprising: a base wafer; a first insulating layer; and a semiconductor layer; wherein the base wafer, the first insulating layer and the semiconductor layer are arranged in an order from the base wafer to the first insulating layer to the semiconductor layer, the first insulating layer is made of an amorphous metal oxide or an amorphous metal nitride, the semiconductor layer includes a first crystal layer, a second crystal layer, and a third crystal layer, the first crystal layer, the second crystal layer and the third crystal layer are arranged in order from the third crystal layer to the first crystal layer to the second crystal layer in such a manner that the third crystal layer is positioned closest to the base wafer, and the first crystal layer is positioned closer to the base wafer than the second crystal layer, the electron affinity E a1 of the first crystal layer is larger than the electron affinity E a2 of the second crystal layer, and the electron affinity E a3 of the third crystal layer is smaller than the electron affinity E a1 of the first crystal layer.