To provide a semiconductor wafer having a wafer, a compound semiconductor layer, a first insulating layer and a second insulating layer, wherein in the depth direction, oxygen atoms and nitrogen atoms are continuously distributed, the number of the nitrogen atoms along the depth direction shows its maximum in the first insulating layer, the total number of third atoms and fourth atoms along the depth direction becomes the largest in the compound semiconductor layer, the number of the oxygen atoms at the interface between the compound semiconductor layer and the first insulating layer is smaller than the number of the oxygen atoms at the interface between the first insulating layer and the second insulating layer.