Depletion-free poly-Si gate high-k CMOSFETs

For the first time, we report poly-Si gate CMOSFETs fabricated using Hf-based stacked gate dielectrics and inverted gate implantation (IGI) that are depletion-free by virtue of the Fermi pinning effect. The sub-threshold and transconductance characteristics of surface channel IGI transistors (which include a P-doped gate for PMOS and a B-doped gate for NMOS) are enhanced because there is no gate depletion. The insertion of a thin AlOx results in some change in threshold voltage for PFETs, which demonstrated controllability of the threshold voltage by gate dielectric stack engineering. By combining IGI and gate dielectric stack engineering, high-performance depletion-free poly-Si gate high-k transistors are possible.