MOSFET characteristics with poly-Si/HfAlON gate stacks using ultra-thin UV-ozone interfacial oxide

This paper conducts a comprehensive evaluation of the electrical characteristics of the poly-silicon gated n-channel metal–oxide–semiconductor field-effect-transistor (nMOSFET) with hafnium–aluminum-oxynitride (HfAlON) gate dielectric with interfacial ultraviolet-ozone (UV-O3) oxide or chemical oxide. Interfacial UV-O3 oxide exhibits well-controlled interfacial properties due to self-saturated growth and thick-oxide-comparable density, which is beneficial to suppress interfacial re-oxidation and reduces surface roughness. Compared with interfacial chemical oxide, the interfacial UV-O3 oxide obviously improves both gate insulating and interface characteristics, including breakdown voltage increments, reduced gate leakage current, and as-deposited traps. In addition, the HfAlON gate stack with UV-O3 interface oxide also shows encouraging nMOSFET device performances, with a small subthreshold swing, high electron mobility, saturation drain current, and negligible stress-induced trap generation. The results clearly suggest that the high-density interfacial UV-O3 oxide possess a high potential to be integrated with further high-k dielectric applications.