Electrical and diffraction characterization of short and narrow MOSFETs on fully depleted strained silicon-on-insulator (sSOI)

摘要

Fully depleted silicon-on-insulator (FDSOI) n and pMOSFETs (Metal-Oxide-Semiconductor-Field-Effect-Transistors) are integrated with a TiN/HfO_2 gate stack on 1.55 GPa strained SOI (sSOI) and 2.1 GPa eXtre-mely strained SOI (XsSOI) substrates. An electron mobility enhancement of 135% for a 77 nm gate width is demonstrated as well as a significant I_(on)-I_(off) improvement for short and narrow nMOS on XsSOI with respect to unstrained SOI. We in-depth analyse this performance boost thanks to the accurate extractions in long and narrow devices of both carrier mobility based on the split-CV method and strain with grazing incidence X-ray diffraction synchrotron experiments. The effective mobility as well as the threshold voltage is systematically extracted as a function of the gate width and the channel orientation for long and narrow n and pMOSFETs. The performance improvement using XsSOI for short and narrow nMOSFETs depends on the channel orientation and is mainly attributed to the tensile strain induced by the TiN gate and to the effective mass improvement under high and non-biaxial strain.