Semiconductor wafer, electronic device, method of performing inspection on semiconductor wafer, and method of manufacturing electronic device

A semiconductor wafer comprising:

• a substrate;
• a buffer layer;
• a first crystalline layer;
• and
• a second layer, wherein
• the substrate, the buffer layer, the first crystalline layer, and the second layer are positioned in order of the substrate, the buffer layer, the first crystalline layer and the second layer,
• the buffer layer and the first crystalline layer are made of a group III nitride layer,
• a bandgap of the first crystalline layer is smaller than a bandgap of the second layer,
• when the semiconductor wafer is formed as a transistor wafer, a channel of a transistor is formed at or near an interface between the first crystalline layer and the second layer, and
• with a first electrode and a second electrode, electrically connected to the channel, provided closer to a front surface than the channel is, and with a third electrode, at which an electric field is applicable to a spatial region positioned between the channel and the substrate, provided closer to a back surface than the channel is, when space charge redistribution, for emitting electrons and holes from a bandgap of a crystal positioned in the spatial region, is achieved by applying negative voltage to the third electrode or by applying positive voltage to the second electrode with the first electrode serving as a reference, an electron emission speed in the space charge redistribution is higher than a hole emission speed.