Study of Mobility for HfO2 dielectric FDSOI-UTTB pMOS under substrate biases

In this work the variation of the FDSOI-UTTB p-MOS mobility is studied for different biases of the buried oxide. Two dielectrics are considered: HfO2 (high-k) with 8A-EOT and a SiON reference. The substrate biases (through the buried oxide) enables a mobility of about 150 cm2/V.s (90% improvement) similar to the SiON reference (with back bias) and close to the results obtained for conventional high-k n-MOS. This 90% improvement is explained by a based physics model which describes a variation of the inversion charge centroid towards the buried oxide for large substrate biases.