Patent ID: 9034741
Filing Date: 2015-05-19
Classification: H01L

Abstract:
1. A method of forming a semiconductor device comprising the steps of: forming a source recess and a drain recess in a semiconductor substrate on opposing sides of a gate positioned above the semiconductor substrate; forming an epitaxial halo region at the bottom of the source and drain recesses lower than a channel region, wherein the epitaxial halo region comprises growing a sacrificial layer including a silicon-germanium or carbon-doped silicon material with the corresponding p-type or n-type dopant; etching the source and drain recesses in the semiconductor substrate to form sigma-shaped source and drain recesses, wherein a portion of the epitaxial halo region remains on opposing lower sides of the sigma-shaped source and drain recesses; epitaxially growing an embedded halo region along a perimeter of each of the sigma-shaped source and drain recesses; removing a bottom area of the embedded halo region along the perimeter of both the sigma-shaped source and drain recesses; and epitaxially growing a stressor material to fill the sigma-shaped source and drain recesses, wherein the filled sigma-shaped source and drain recesses form source and drain regions for conducting current through the channel.