Abstract Reoxidized nitrided oxides (ONO) will be used in ULSI technology to improve the properties of thin gate dielectrics as high breakdown fields, radiation resistance, and diffusion barriers. The ONO structures analyzed in our study are fabricated in a rapid thermal processing reactor (RTP) using oxygen and ammonium ambients. Typical data for the sequential processing mode are: rapid thermal oxidation (RTO) in oxygen atmosphere at 1100° C and rapid thermal nitridation in ammonium atmosphere (RTN) at 1050° C followed by RTO at 1150° C. Due to the complexity of the growth process it is very important to verify the resulting layers with analytical methods. The whole structure is only about 250 Å thick. To analyse the sequence, composition and thickness of the layers, the depth resolution of SIMS is necessary. On the other hand, for quantification, RBS and NRA can be used. When the bulk signal is suppressed by channelling, the signal of oxygen, and in special cases nitrogen, can be evaluated from the He + backscattering spectrum. For nuclear reaction analysis, the reactions of nitrogen with deuterium are used. The combination of SIMS and the accelerator techniques allow quantitative analysis and depth profiling of this structure.