Patent ID: 8105908
Filing Date: 2012-01-31
Classification: H01L

Abstract:
1. A method of forming a transistor on a substrate having a desired channel stress, comprising: a) providing a transistor having a channel region having a preexisting channel stress; b) determining the effect on the preexisting channel stress of changing the preexisting values of at least three parameters that together affect uniaxial local strain on selected regions of the transistor, the parameters affecting uniaxial local strain selected from the group consisting of source/drain elevation, source/drain silicon and germanium concentration, source/drain dimensions, source/drain facet length, source/drain facet angle, source/drain dopant concentration, etch stop composition or dimensions, number of etch stop layers, and spacer dimensions; c) selecting the changes in the preexisting values of said at least three parameters for design of a transistor having a channel region having the desired channel stress; and d) manufacturing a transistor having the selected changes, thereby providing a transistor having a channel region having the desired channel stress, wherein manufacturing the transistor further comprises forming at least first and second etch stop layers and cooling the substrate between formation of the first and second etch stop layers.