Optimization of nitrided gate dielectrics by plasma-assisted and rapid thermal processing

This article addresses several aspects of nitrogen atom (N atom) incorporation into ultrathin gate oxides including: (i) monolayer incorporation of N atoms at the Si-SiO(2) interfaces to reduce tunneling currents and improve device reliability; and (ii) the incorporation of silicon nitride films into stacked oxide-nitride (ON) gate dielectrics to (a) increase the capacitance in ultrathin dielectrics without decreasing film thickness, and (b) suppress boron atom (B atom) diffusion from p(+) polycrystalline Si gale electrodes through the dielectric layer to the Si substrate channel region. The results of this article demonstrate that these N-atom spatial distributions can be accomplished by low thermal budget, single wafer processing which includes (i) low-temperature (300 degrees C) plasma assisted oxidation, nitridation, and/or deposition to achieve the desired N-atom incorporation, followed by (ii) low thermal budget (30 s at 900 degrees C) rapid thermal annealing to promote chemical and structural bulk and interface relaxation. (C) 1998 American Vacuum Society.