Comparative study between Si (110) and (100) substrates on mobility and velocity enhancements for short-channel highly-strained PFETs

Mobility and velocity enhancements of hole on Si (110) and (100) substrates are accurately investigated for short-channel highly-strained pFETs. Local channel stress in short gate length is successfully observed for damascene gate pFETs with stressors by UV-Raman spectroscopy. A high channel stress of −2.4 GPa is measured for a 30-nm gate length device. Hole mobility and saturation velocity are precisely investigated for the −2.1 GPa stressed pFETs with a effective gate length of 30 nm. The mobility and velocity enhancements under high channel stress for (100) substrate are larger than those for (110). Therefore, saturation current on (100) is larger than that on (110) for pFETs with higher channel stress and shorter gate length.