Ultra-thin oxynitride gate dielectrics for 0.18 μm CMOS and beyond

Summary form only given. N₂O- and/or NO-based oxynitrides are promising candidates for ultra-thin gate dielectrics (<4 nm) in dual-gate CMOS technologies for their superior boron diffusion barrier characteristics. Despite of their importance in the technologies for sub-0.18 μm CMOS generations, systematic studies which correlate interfacial properties with MOSFET characteristics (including reliability issues) have not yet been fully carried out. In this paper, MOSFET characteristics such as V_th variation, I _d, μ_eff and robustness to plasma charging effects are discussed in relation to the interfacial properties of oxynitride gate dielectrics studied by means of TEM, XPS and FT-IR for N ₂O and NO oxynitrides ranging between 2-5 nm. It was found that MOSFETs with NO oxynitrides result in superior characteristics, because of the smoother interface and tighter trivalent Si-N bonding at the Si/oxynitride interface