Evidence for a Very Small Tunneling Effective Mass (0.03 $m_{0}$ ) in MOSFET High- $k$ (HfSiON) Gate

We have recently conducted experimental and modeling tasks on TaC/HfSiON/SiON n-type MOSFETs, leading to an effective mass of 0.03m₀ for 2-D electrons tunneling in high-k HfSiON dielectrics. In this letter, we present extra evidence obtained from complementary MOSFETs undergoing the same TaC/HfSiON/SiON processing, which shows that such a very small tunneling effective mass is existent not only for 3-D electrons but also for 2-D holes. This new finding is very important because it can substantially enhance the current understanding of gate tunneling leakage suppression in metal-gate high-k MOSFETs.