FinFETs with Strained Well Regions

摘要

A device includes a substrate and insulation regions over a portion of the substrate. A first semiconductor region is between the insulation regions and having a first conduction band. A second semiconductor region is over and adjoining the first semiconductor region, wherein the second semiconductor region includes an upper portion higher than top surfaces of the insulation regions to form a semiconductor fin. The second semiconductor region also includes a wide portion and a narrow portion over the wide portion, wherein the narrow portion is narrower than the wide portion. The semiconductor fin has a tensile strain and has a second conduction band lower than the first conduction band. A third semiconductor region is over and adjoining a top surface and sidewalls of the semiconductor fin, wherein the third semiconductor region has a third conduction band higher than the second conduction band.

主权项

1. A method comprising:
forming a semiconductor fin protruding higher than top surfaces of insulation regions, wherein the insulation regions are on opposite sides of the semiconductor fin; recessing a first sidewall and a second sidewall of the semiconductor fin, wherein the first sidewall and the second sidewall are opposite sidewalls of the semiconductor fin; performing a first epitaxy to grow a semiconductor layer, wherein the semiconductor layer comprises a first sidewall portion contacting the first recessed sidewall of the semiconductor fin, and a second sidewall portion contacting the second recessed sidewall; forming a gate dielectric over the semiconductor fin; and forming a gate electrode over the gate dielectric.