Fabrication of buried layers of SiO 2 and Si 3N 4 a using ion beam synthesis

Abstract

The properties of buried layers produced by the implantation of high doses of energetic light ions O+ and N+ are reviewed. Similarities and differences in the as implanted and annealed structures are discussed as are the effects of variations in the anneal temperature, time and ramp-rate. To assess the factors governing the interfacial displacements of the growing buried layer with respect to the silicon, experiments utilising buried marker layers and involving sequential implants of O+ or N+ ions were undertaken. These confirmed the results of 18O+ and 15N+ tracer experiments by showing that during implantation the back interface of the buried layer remains effectively fixed while the front interface is displaced towards the silicon surface. During the subsequent anneal redistribution of the implanted species occurs but again this effect is most marked at the front interface.