Demonstration of Ge pMOSFETs with 6 Å EOT using TaN/ZrO2/Zr-cap/n-Ge(100) gate stack fabricated by novel vacuum annealing and in-situ metal capping method

The superior gate stack was fabricated by employing novel high vacuum annealing followed by in-situ metal capping method to suppress GeO_x regrowth. Less GeO volatilization induces less Ta diffusion into gate oxide which reduces leakage current and enables further scaling. With ZrO₂/Zr-cap stack, highly scaled Ge (100) pMOSFETs have been demonstrated which shows extremely low EOT (6.06 Å), low gate leakage current of 250 nA/cm²@|V_g-V_FB|=1V, superior SS of 70 mV/dec, and 110 cm²/Vs of peak hole mobility.