Impact of Al-, Ni-, TiN-, and Mo-metal gates on MOCVD-grown HfO₂ and ZrO₂ high-κ dielectrics

In this work we compare the impacts of nickel (Ni), titanium-nitride (TiN), molybdenum (Mo), and aluminium (Al), gates on MOS capacitors incorporating HfO₂- or ZrO₂-dielectrics. The primary focus lies on interface trapping, oxide charging, and thermodynamical stability during different annealing steps of these gate stacks. Whereas Ni, Mo, and especially TiN are investigated as most promising candidates for future CMOS devices, Al acted as reference gate material to benchmark the parameters. Post-metallization annealing of both, TiN- and Mo-stacks, resulted in very promising electrical characteristics. However, gate stacks annealed at temperatures of 800 °C or 950 °C show thermodynamic instability and related undesirable high leakage currents.