Impact of post-deposition-annealing on the electrical characteristics of HfO _x N _y gate dielectric on Ge substrate

We systematically investigated the effect of post-deposition-annealing (PDA) on the electrical characteristics of Ge MOS capacitors with hafnium-oxynitride gate dielectric. The higher PDA temperature and longer PDA time was found to obtain the lower equivalent oxide thickness (EOT) of HfO _x N _y /Ge gate stack, however, with a larger hysteresis width. A lower EOT of 19.5 Å with a low leakage current of 1.8 × 10 ^-5 A/cm ² at V _G = -1V was achieved after 600 °C annealing for 5 min. The improved capacitor properties after the PDA may be closely related to the different compositions and thicknesses of the resultant interfacial layers.