Patent ID: 8264001

Claim:
A semiconductor wafer comprising: a substrate; a buffer region formed on one main surface of the substrate and formed from a compound semiconductor; and a main semiconductor region formed on the buffer region and formed from a compound semiconductor; wherein the buffer region includes a first multi-layer structured buffer region and a second multi-layer structured buffer region and a single layer structured buffer region arranged between the first multi-layer structured buffer region and the second multi-layer structured buffer region, both multi-layer structured buffer regions being stacked with a plurality of alternating first layers and second layers; the first layer is formed from a compound semiconductor which has a lattice constant smaller than a lattice constant of a material which forms the substrate; the second layer is formed from a compound semiconductor which has a lattice constant between a lattice constant of a material which forms the substrate and a lattice constant of a material which forms the first layer; and the single layer structured buffer region is thicker than the first layer and the second layer, and is formed from a compound semiconductor which has a lattice constant between a lattice constant of a material which forms the first layer and a lattice constant of a material which forms the second layer.