Patent ID: 9559237
Date: 2017-01-31
CPC Classifications: H01L,Y02E,Y02P

Claim:
1. A semiconductor structure comprising: a first semiconductor layer having a first bandgap and a first lattice constant; a second semiconductor layer having a second bandgap and a second lattice constant, the second lattice constant being lower than the first lattice constant; and a transparent metamorphic buffer layer disposed between the first semiconductor layer and the second semiconductor layer, the transparent metamorphic buffer layer having a constant or substantially constant bandgap and a varying lattice constant, the varying lattice constant being matched to the first lattice constant adjacent the first semiconductor layer and matched to the second lattice constant adjacent the second semiconductor layer, wherein the transparent metamorphic buffer layer comprises a first portion comprising Al wherein the second portion of the transparent metamorphic buffer layer comprises at least three compositionally graded steps comprising Ga