Search

Abstract: 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. [Copyright &y& Elsevier]

New three-dimensional device concepts are considered necessary for the ultimate scaling of the gate length of metal-oxide-semiconductor field effect transistors (MOSFETs). Both Triple-Gate field effect transistors and FinFETs require a gate etch process with excellent selectivity over the gate oxide material. In this work, a highly selective, anisotropic gate etch process using HBr and O2 as the reactive gases in an inductively coupled plasma reactive ion etch tool is described. Polysilicon thickness measurements have been taken to calculate etch rate and uniformity. Polysilicon wafers for each experimental condition were given different overetch times and SiO2 losses were plotted against time, with the gradient yielding the SiO2 etch rate. The optimized etch process yields excellent results for nanoscale polysilicon gates. [Copyright &y& Elsevier]