Impacts of notched-gate structure on contact etch stop layer (CESL) stressed 90-nm nMOSFET

[[abstract]]In this letter, mobility improvements by stress contact etch stop layer (CESL) in a strained 90-nm nMOSFET, with and without notched-gate structure, were studied in detail. Compared to the conventional vertical gate, a device with notched gate shows an extra 7% NMOS ION enhancement for the increased stress in the channel region and the less effect of the halo-implanted impurity on channel. Both simulations with TCAD software and measurements confirm that the notched-gate structure efficiently enhances the generation of high tensile stress on the channel region from the CESL and more localized pocket implant