To meet HP and LP circuit requirements, increasing channel mobility is required to boost transistor performance and/or reduce Vdd for lower power dissipation without performance penalty. The ultra-thin body (UTB) devices with undoped and strained channels can be used to control the SCE and reduce the sub-threshold leakage for scaling and low power dissipation. Implementing strained-silicon is not just a substrate change; strained- Si will require much more extensive work as transistor scaling continues.