Ultrascaled hafnium silicon oxynitride gate dielectrics with excellent carrier mobility and reliability

A hafnium silicon oxynitride gate dielectric with a universal channel mobility of similar to 90% at 1 MV/cm, equivalent oxide thickness of approximately 1 nm, and leakage current 200 x less than SiO2 is reported. X-ray photoelectron spectroscopy results suggest that the small peak mobility loss observed in scaled HfSiON may be attributed to increased Si-N bonding near the silicon interface. In accordance with these mobility results, the Si-N:Hf-N bond ratio decreases with increasing HfSiON physical thickness. Threshold voltage instability at 1 nm equivalent oxide thickness is less than 10 mV after a 1000 s stress at 22 MV cm. Delta V-TH monotonically increases with HfSiON physical thickness. This is associated with greater crystallization in thicker HfSiON films. (c) 2005 American Institute of Physics.