Patent ID: 8361851
Filing Date: 2013-01-29
Classification: H01L

Abstract:
1. A method for manufacturing an N-type field effect transistor with enhanced carrier mobility, comprising: forming an N-type field effect transistor on a substrate, the transistor comprising a gate stack, a source region, and a drain region, the gate stack comprising a gate dielectric layer, a metal gate layer, and a dummy gate layer; forming a contact etch stopper layer to cover the source region, the drain region, and the gate stack of the transistor; forming a first pair of contact holes on the source region and the drain region, respectively, in the contact etch stopper layer, the contact holes being adjacent to the gate stack; forming a material having a tensile stress in the first pair of contact holes to apply a tensile stress to the channel region of the transistor; removing the dummy gate layer to increase the tensile stress in the channel region; and after removing the dummy gate layer, forming a stressed layer having a compressive stress on the metal gate layer, so as to further increase the tensile stress in the channel region.