Effects of Channel Orientations, High-? Gate Stacks and Stress on UTB-FETs: A QDD Simulation Study

In this work we propose a unified model for the low-field effective electron mobility in SOI and DG-MOSFETs with ultrathin SiO
₂
/HfO
₂
gate stacks, different substrate and channel orientations and uniaxial stress conditions.The model accounts for quantum-confinement effects in the MOSFET channel. Next, we apply this mobility model to a 1D quantum drift-diffusion (QDD) transport model in order to investigate the extent to which the low-field mobility impacts the I-V characteristics. Short (L
_g
= 22 nm) DGFETs,where mobility is affected by quantum-confinement effects, ultrathin SiO
₂
/HfO
₂
gate stacks and metal gate,have been investigated. Finally, the correlations between the mobility enhancement induced by uniaxial stress in a 22 nm DG-FET, the on-current and transconductance are examined.