80 nm poly-silicon gated n-FETs with ultra-thin Al₂O₃ gate dielectric for ULSI applications

Abstract

This work demonstrates the integration of Al2O3 gate-dielectrics into a sub 0.1μm n-MOS process using polycrystalline silicon gates. Devices incorporating Al2O3 films with a dielectric constant ε∼11 and electrical thickness tqm< 1.5 nm have been fabricated. Gate leakage currents are ∼100 times lower than those found in SiO2 films of equivalent thickness. Encouraging device characteristics are shown. Charging due to slow states and/or fixed charge have been shown to be in the 100 mV range which may be related to the somewhat reduced mobility. The room temperature reliability of these devices based upon the values of β (Weibull slope) and γ (voltage acceleration) suggest that the Al2O3 lifetime may exceed that of SiO2 films.