Comparison of the Interfacial Stress Resistance in Rapid Thermally Processed Thin Dielectrics

The dielectric-silicon interface stress resistance of conventional furnace oxides and those formed using rapid thermal oxidation (RTO) with and without rapid thermal nitridation (RTN) are compared. The stress resistance is deduced from the change in the fast interface trap density and flatband voltage under high field constant current stress conditions. In the thinner dielectrics (10-13 nm), the interfacial stress resistance of the RTN dielectrics at -9 MV/cm is a factor of 2 greater than in the thermal oxides. For the thicker RTN layers (34-40 nm) the stress resistance was ~25% less than the thermal oxides due to the reduced interfacial nitrogen concentration. However in the thinner dielectrics, the higher nitrogen concentration in the RTN layers leads to a factor of ~8 greater shift in flatband voltage compared to the thermal oxides.