Effects of High-Pressure H₂ and D₂ Post-Metallization Annealing on the Electrical Properties of HfO₂/Si_0.7Ge_0.3

High-pressure annealing (HPA) in both hydrogen (H₂) and deuterium (D₂) environments is attempted on HfO₂/Si_0.7Ge_0.3 capacitors as a post-metallization annealing (PMA) approach. As compared with conventional forming gas annealing (FGA), a dramatic reduction in the interface state density (D_it) is achieved after both H₂- and D₂-HPA processes at the equivalent temperature (300 °C) and time (30 min) by effectively passivating the Ge-induced dangling bonds at the interface region. Meanwhile, the stress-induced leakage current characteristics are only improved by the D₂-HPA process, indicating that D-passivation is more resistant to external electrical stress than H-passivation. As the PMA temperature increases to 500 °C, both HPA further decreases the D_it, but a significant increase is observed for FGA. In addition, the PMA temperature-dependent degradation of leakage current is less in HPA than in FGA.