Electrical characteristics of SiGe MOSFETs integrated with Tantalum or Titanium oxynitride higher-k gate dielectrics

Metal oxide semiconductor field effect transistors (MOSFET) with SiGe channel and higher-k gate dielectric are studied in this work. Samples with TaON/HfO₂ or TiON/HfO₂ stacks show larger drain current, transconductance, and smaller subthreshold swing than that with single HfO₂ layer. In addition, the reliability of SiGe MOSFET device is clearly improved with TaON/HfO₂ stacks in terms of degradation of Gm and Vth after hot-carrier stress. The integration of SiGe channel with TaON/HfO₂ higher-k dielectric is useful for high-performance MOSFETs.