Patent ID: 6864159

Claim:
A method for fabricating a III-V compound semiconductor comprising a step of successively epitaxially growing thin films to fabricate a III-V Group compound semiconductor composed of a buffer layer having a multilayer structure of thin-filmed layers of compositions represented by Al xi Ga 1-xi As (0≦xi<1, i=1, 2, . . . n) formed on a flat GaAs substrate and an upper multilayer structure of layers of compositions represented by Al yj Ga 1-yj As (0≦yj<1,j=1, 2, . . . ) formed on the buffer layer, wherein the Al content of an uppermost thin-film layer among the buffer layers is lower than the Al content of an adjacent upper multilayer structure formed on the uppermost thin-film layer in which step a growth rate of the adjacent layer is made slower than a growth rate of the uppermost layer.