Patent ID: 7851313
Filing Date: 2010-12-14
Classification: H01L

Abstract:
1. A method of forming strained silicon alloy trenches within a semiconductor substrate, comprising: forming sidewall spacers on a gate stack of the semiconductor substrate; exposing a photoresist layer of the semiconductor substrate to a mask pattern; etching the photoresist layer and underlying semiconductor substrate in accordance with the mask pattern to form trenches within the semiconductor substrate, wherein the trenches are selectively etched to produce a slower etch rate along a first crystallographic direction relative to an etch rate along second and third crystallographic directions; and aligning the trenches to the sidewall spacers to minimize a separation distance between the trenches and the gate stack; epitaxially growing strained silicon alloy within each trench, wherein a shape of the trench maximizes stress at the surface of the semiconductor substrate relative to stress induced below the surface of the semiconductor substrate.