Patent ID: 8497168
Filing Date: 2013-07-30
Classification: H01L

Abstract:
1. A method of adjusting carrier mobility in semiconductor devices comprising the steps of depositing a first stressed film on a wafer including first and second transistors to create a stress in the channels of the transistors, partially removing said first stressed film to relieve said stress from a channel of one said transistor such that a portion of said first stressed film remains on a surface adjacent a channel region of another said transistor, forming a dielectric layer capable of isolating shear forces applied to opposite surfaces thereof on said portion of said first stressed film before or after said step of partially removing said first stressed film, depositing a second stressed film over said first and second transistors to apply a second stress to the channel of the transistor having said first stressed film removed whereby said second stressed film applies stress to said another transistor while stress applied to said transistor by said first stressed film is substantially unaffected, and substantially completing said transistor and said another transistors with said another transistor having both first and second stressed films applied thereto.