Low temperature oxynitridation of SiGe in NO/N2O ambients

X-Ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS) and spectral ellipsometry have been used to study sub-35 Angstrom low temperature oxynitrides of SiGe. The oxynitridations steps have been performed at 550 degreesC and 650 degreesC, while the oxynitridation feed gases have been preheated to 900 degreesC and 1000 degreesC, respectively, before entering the reaction zone. XPS and SIMS data suggests that NO-assisted oxynitridation incorporates more nitrogen than the N2O-assisted one, while there is minimal Ge segregation towards the dielectric/substrate interface in both oxynitridation processes. SIMS data suggests that the nitrogen is distributed throughout the film in contrast to high temperature Si oxynitridation where nitrogen incorporation takes place near the dielectric/substrate interface. Spectral Ellipsometry has been used to measure the final thickness of the oxynitrides film. These results are discussed in the context of an overall mechanism of the oxynritridation of SiGe.