This research analyzes internal stress in the N-MOSFET. The research has two parts. First, we explore the effect of N-MOSFET channel stress when CESL layer is not utilized. The dimensional effect of spacer upon channel stress in N-MOSFET with variant width of ONO (oxide, nitride, oxide) is compared. Second, with stress applied to CESL and the spacer stressor, long/short channel effects are analyzed. It is demonstrated that when the thickness of CESL and the height of gate increase, the channel stress under the gate dielectric layer becomes tensile, and the performance is improved in the short channel, resulting in the improved performance in the whole N-MOSFET. Therefore, better device characteristics can be expected through the approach disclosed in this paper.

It is demonstrated that the strained-Si can enhance the channel stress with the contact etching stop layer (CESL) stressor. In addition to CESL, this article also includes ONO spacer and investigates the impact of ONO spacer thickness on the channel stress. It is found that the channel stress increases when the nitride thickness of the ONO spacer increases. On the other hand, the stress distribution is simulated and analyzed for the devices with or without CESL stressor. Generally speaking, based on the simulation results, the channel stress of MOSFET devices increases when the nitride stressor of ONO spacer and/or CESL increases.