Multiple threshold voltage FinFETs

A method of forming a plurality of fins having different threshold voltages comprising:

• providing a first semiconductor layer in a plurality of regions, wherein the first semiconductor layer has a starting thickness across the plurality of regions;
• recessing the first semiconductor layer in a first recessed region, wherein the first semiconductor layer has a first recessed thickness in the first recessed region;
• recessing the first semiconductor layer in a second recessed region, wherein the first semiconductor layer has a second recessed thickness in the second recessed region, and the second recessed thickness is less than the first recessed thickness;
• forming a second semiconductor layer on the first semiconductor layer in the first recessed region and in the second recessed region;
• merging the first semiconductor layer and the second semiconductor layer in regions having the second semiconductor layer, wherein a first merged semiconductor is formed in the first recessed region and a second merged semiconductor is formed in the second recessed region;
• and
• forming first concentration fins from the first merged semiconductor and second concentration fins from the second merged semiconductor.