[招待論文]Stress and Surface Orientation Engineering in Scaled CMOSFETs Considering High-Field Carrier Transport

摘要

We present the systematic study on the performance of short-channel and strained (100) and (110) n/pMOSFETs. Saturation drain current (I_(dsat)) of short-channel (110) nFETs approaches (100) nFETs as a result of strong velocity saturation in (100) nFETs. Meanwhile, I_(dsat) of short-channel (110) pFETs are still superior to (100) pFETs due to weaker velocity saturation than nFETs. Carrier velocity (v) and I_(dsat) increase by strain is determined not only by low-field mobility (μ) enhancement (△μ/μ) but also by the modulation of saturation velocity (v_(sat)). It is found that v_(sat) increases more by strain in smaller-△μ/μ devices. As a result, △v/v of (100)/(110) n/pFETs converge in sub-30nm regime, because the difference of △μ/μ is compensated by v_(sat) change. The superiority of (110) CMOS to (100) CMOS is maintained at highly-strained conditions.