Novel TDDB mechanism for p-FET accelerated by hydrogen from HfSiON film

Time Dependent Dielectric Breakdown (TDDB) in p-FETs with HfSiON/SiO₂ gate stacks under negative bias stress has been studied. It is shown that the shape parameter of Weibull distribution of T_bd, β, is very small value independent of gate electrode materials. This small β seems to arise from the interface layer (I.L.) breakdown. Further experimental result reveals the existence of additional interface layer degradation mechanisms due to hydrogen in HfSiON. The reduction of hydrogen amount in high-k dielectrics leads to the longer-term reliability in metal-gate/high-k gate stacks.