Study of substrate orientations impact on Ultra Thin Buried Oxide (UTBOX) FDSOI High-K Metal gate technology performances

In this paper, we compare the electrical properties of Ultra Thin Buried Oxide (UTBOX) Fully Depleted Silicon On Insulator (FDSOI) MOS devices for rotated and non-rotated substrate with different gate lengths. We found a significant performance enhancement on FDSOI PMOSFETs for rotated substrates as expected, while keeping a good control of short channel effects. Surprisingly, to a lower extent, an improvement is also found for NMOS devices. We have also studied the carrier mobility degradation as a function of temperature and we point out the contribution of different mechanisms that reduce the mobility such as impurity Coulomb scattering, phonons and neutral defects as a function of gate length. We find that there is no significant effect of rotated substrate on the mobility degradation at room temperature. All these results are discussed and possible explanations are also given.