Nitrogen depth profiling in ultrathin silicon oxynitride films with high-resolution rutherford backscattering spectroscopy

Nitrogen depth profiles in ultrathin silicon oxynitride films (2.5-8 nm) ar e measured by high-resolution Rutherford backscattering spectroscopy (HRBS) . In order to reduce the large background due to the substrate silicon, HRB S spectra are measured under [111] channeling conditions. It is demonstrate d that the HRBS/channeling technique provides the absolute concentration va lues and a depth resolution of sub-nm can be achieved. The nitrogen profile s are also measured by secondary ion mass spectroscopy (SIMS) and Auger ele ctron spectroscopy (AES). The AES result roughly agrees with the HRBS resul t, while the SIMS result underestimates the nitrogen concentration.