Hafnium oxide gate stack prepared by in situ rapid thermal chemical vapor deposition process for advanced gate dielectrics

A high-quality HfO ₂ gate stack with equivalent oxide thickness (EOT) of 7.8 Å and a leakage current of J _g=0.5mA/cm ² @ V _g=-1.0V has been achieved by an in situ rapid thermal chemical vapor deposition process. It is found that both NH ₃-based interface layer and N ₂ postdeposition annealing are very effective in reducing EOT and leakage, and at the same time, improving film qualities. These HfO ₂ gate stacks show negligible frequency dependence, small hysteresis in capacitance-voltage (C-V) and weak temperature dependence of the leakage current. They also show negligible charge trapping at high voltage stress.