Effects of High-Pressure H2 and D2 Post-Metallization Annealing on the Electrical Properties of HfO2/Si0.7Ge0.3

초록

High-pressure annealing (HPA) in both hydrogen (H-2) and deuterium (D-2) environments is attempted on HfO2/Si0.7Ge0.3 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 H-2- and D-2-HPA processes at the equivalent temperature (300 degrees 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 D-2-HPA process, indicating that D-passivation is more resistant to external electrical stress than H-passivation. As the PMA temperature increases to 500 degrees 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.

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