Patent ID: 9142474
Filing Date: 2015-09-22
Classification: H01L

Abstract:
1. A fin field effect transistor (FinFET) comprising: a substrate comprising a major surface; a fin structure protruding from the major surface comprising: a lower fin portion comprising a first semiconductor material having a first lattice constant; an upper fin portion comprising a second semiconductor material having a second lattice constant greater than the first lattice constant; a middle fin portion between the lower fin portion and upper fin portion, wherein the middle fin portion comprises a third semiconductor material having a third lattice constant between the first lattice constant and the second lattice constant; and a passivation structure surrounding the fin structure comprising: a lower passivation portion surrounding the lower fin portion comprising a first oxynitride of the first semiconductor material; an upper passivation portion surrounding the upper fin portion comprising a second oxynitride of the second semiconductor material; and a middle passivation portion between the lower passivation portion and upper passivation portion, wherein the middle passivation portion surrounding the middle fin portion comprises a third oxynitride of the third semiconductor material.