H2 High Pressure Annealed Y-Doped ZrO2 Gate Dielectric With an EOT of 0.57 nm for Ge MOSFETs.

We report on the impact of H2 high pressure annealing (H2-HPA) on a Y-doped ZrO2 (Y-ZrO2)/GeOx/Ge gate stack. In this paper, compared to conventional forming gas annealing (FGA), the H2-HPA increased the k-value of the Y-doped ZrO2 gate dielectric to as high as 47.8 by enhancing the crystallization of the Y-ZrO2. This process can achieve an aggressively scaled equivalent oxide thickness (EOT) of 0.57 nm with an extremely low gate leakage current (Jg) of $ {4.5} \times {10}^{- {6}}$ A/cm2. In addition, the H2-HPA effectively passivated the dangling bonds and reduced the interface trap density (Dit) to as low as ${3.4} \times {10}^{ {11}}$ eV−1cm−2. The Ge pMOSFETs of the Y-ZrO2 with H2-HPA led to a ~ 70% improvement in the effective hole mobility compared to the counterpart device with the conventional FGA. The device with H2-HPA also showed an improved subthreshold swing (SS) value of 93 mV/dec compared to that with the FGA (135 mV/dec). [ABSTRACT FROM AUTHOR]