Patent ID: 9589849
Date: 2017-03-07
CPC Classifications: H01L

Claim:
1. A method, comprising: forming a plurality of fin-formation trenches in a substrate to define a plurality of substrate fins: over-filling said plurality of fin-formation trenches with an insulting material; performing a recess etching process on said plurality of substrate fins to remove portions of said substrate fins and thereby define a plurality of recessed substrate fins and a fin cavity above each of said recessed substrate fins that is bounded by said insulting material; forming a strain relaxed buffer material in each of said fin cavities on said recessed substrate fins; and forming a plurality of initial fins in each of said fin cavities on said strain relaxed buffer material, said plurality of initial fins having a same initial axial length and a same initial strain along a current transport direction of said plurality of initial fins; performing at least one etching process so as to cut a first fin to a first axial length and to cut a second fin to a second axial length that is less than said first axial length, wherein said cut first fin retains a first amount of said initial strain and said cut second fin retains zero of said initial strain or a second amount of said initial strain, said second amount being less than said first amount; forming a first gate structure for a first FinFET device around a portion of said cut first fin; and forming a second gate structure for a second FinFET device around a portion of said cut second fin.