An Investigation of the Effect of Elastic Constants of Spacer in n-FETs CESL Stressor

The strained-Si approach from the contact etching stop layer (CESL) stressor with two kinds of Young's modulus spacer has been investigated. From the TSUPREM4 simulation of the CESL tensile stressor, the tensile channel stress induced by the SiN spacer material is found to be 60% more than that by the oxide spacer material. With the use of a tensile CESL stressor for the 90-nm n-FETs, an extra 10% enhancement in drive current I
_Dsat
was obtained in the device with a high Young's modulus (270-290 GPa) SiN spacer as compared with that with a low Young's modulus (66 GPa) SiO
₂
spacer. The electrical data are in good agreement with the prediction of the stress simulation.