High-Field Electron Mobility in Biaxially-tensile Strained SOI: Low Temperature Measurement and Correlation with the Surface Morphology

The high field mobility enhancement in sSOI devices is still unexplained as for now. This work proposes an experimental and theoretical investigation of the physical mechanisms responsible for such a gain. For the first time, we show by atomic force microscopy (AFM) measurements that the surface roughness of sSi is drastically reduced compared to unstrained Si. Introduced into a Kubo-Greenwood model, this improved roughness perfectly reproduces the experimental mobility enhancement at high effective fields (ges1 MV/cm) for a wide range of temperature (50 K-300 K).