Passivation and interface state density of SiO2/HfO2-based/polycrystalline-Si gate stacks

We demonstrate that a forming gas annealing temperature of 520 °C significantly improves interface state passivation for SiO2/HfO2-based/polycrystalline-Si gate stacks as compared to annealing at 420 °C normally used for SiO2/polycrystalline-Si gate stacks. We also show that the initial interface state density is dependent upon the interfacial SiO2 preparation, whereby a chemically grown oxide has a higher initial interface state density as compared to a thermally grown oxide.