Semiconductor wafer, method of producing semiconductor wafer and electronic device

A method of producing a semiconductor wafer, the method comprising:

• forming a compound semiconductor layer on a wafer;
• forming a first insulating layer on the compound semiconductor layer by CVD by using a first gas and a second gas as source gases, and at a wafer temperature of 250° C. or higher and 450° C. or lower;
• and
• after forming the first insulating layer, forming a second insulating layer by ALD by using a third gas and a fourth gas, wherein
• the first gas is a gas containing a gaseous compound of first atoms,
• the second gas is one or more gases selected from the group consisting of gaseous nitrogen compounds and nitrogen molecules,
• the third gas is a gas containing a gaseous compound of second atoms,
• the fourth gas is one or more gases selected from the group consisting of gaseous oxygen compounds and oxygen molecules,
• the first atoms are one or more atoms selected from the group consisting of all the metallic atoms, B atoms, Si atoms, As atoms, Te atoms and At atoms, and
• the second atoms are one or more atoms selected from the group consisting of all the metallic atoms,
• in the depth direction that is from a surface of the second insulating layer to the wafer, the oxygen atoms and the nitrogen atoms are continuously distributed in the second insulating layer, the first insulating layer and the compound semiconductor layer,
• the number of atoms per unit volume of the nitrogen atoms along the depth direction shows its maximum in the first insulating layer,
• the total number of atoms per unit volume of the third atoms and fourth atoms along the depth direction becomes the largest in the compound semiconductor layer, and
• the number of atoms per unit volume of the oxygen atoms at a first interface which is the interface between the compound semiconductor layer and the first insulating layer is smaller than the number of atoms per unit volume of the oxygen atoms at a second interface which is the interface between the first insulating layer and the second insulating layer.