Mobility and Dielectric Quality of 1-nm EOT HfSiON on Si(110) and (100)

In this paper, we study the mobility and dielectric quality of MOSFETs with 1-nm Equivalent Oxide Thickness (EOT) grown on substrates with different crystallographic orientations: (100) and (110). Measurement techniques based on RF split CVs (150 MHz) on short-channel devices (down to 80 nm) are used to extract the electrical parameters. Despite the different oxidation growth rates expected by changing the substrate orientation, we obtain similar EOT values even for thin dielectrics (1 nm). Further identical gate overlaps are found regardless of the substrate orientation. The mobility in (110) substrate shows a large improvement for p-MOS. This improvement is independent of the EOT (down to 1 nm) and the length scaling. Although larger interface states were observed by charge pumping for the (110) devices, low-temperature mobility study suggests that the remote charge scattering, and therefore, the gate stack quality is the same.