Performance improvement of self-aligned HfO2/TaN and SiON/TaN nMOS transistors

Direct-etched HfO2/TaN nMOS transistors were fabricated. The performance of the transistors with aggressively scaled EOT is comparable or better than that of SiO2/poly transistors. The performance enhancement requires a combination of EOT scaling and an appropriate interface layer control. The performance of the direct-etched TaN gated HfO2 based transistors is also compared to the performance of similar TaN gated SiON based transistors. It is observed that for equal gm the leakage is lower for HfO2 based transistors, despite the lower EOT for the HfO2 based devices.