Impact of non uniform strain configuration on transport properties for FD14+ devices

As device dimensions are scaled down, the use of non-geometrical performance boosters becomes of special relevance. In this sense, strained channels are proposed for the 14 nm FDSOI node. However this option may introduce a new source of variability since strain distribution inside the channel is not uniform at such scales. In this work, a MS-EMC study of different strain configurations including non-uniformities is presented showing drain current degradation because of the increase of intervalley phonon scattering and the subsequent variations of transport effective mass and drift velocity. This effect, which has an intrinsic statistical origin, will make necessary further optimizations to keep the expected boosting capabilities of strained channels.