A simple approach to fabrication of high-quality HfSiON gate dielectrics with improved nMOSFET performances

A simple technique to form high-quality hafnium silicon oxynitride (HfSiON) by rapid thermal processing oxidation of physical vapor deposition hafnium nitride (HfN) thin films on ultrathin silicon oxide (SiO₂) or silicon oxynitride (SiON) layer is presented. Metal TaN gate electrode is also introduced into such HfSiON stacks. Excellent performances including large electron mobility (85%SiO₂at0.2 MV/cm), low leakage current (10^-4 of SiO₂), and superior time-dependant dielectric breakdown reliability are achieved in HfSiON/SiO₂ stacks, and these results suggest such stacks are very promising for the low-power SOC applications in the near future. In addition, the improvement of the electron mobility in this HfSiON/SiO₂ stack by a reduction of the border traps in the HfSiON dielectric is demonstrated.