Quantitative investigation of impurity distribution in ZMR SOI layers

Summary form only given. The redistribution of oxygen and nitrogen in zone-melting recrystallized (ZMR) layers is discussed. During the ZMR process the silicon layer is exposed on both sides to SiO₂ layers at very high temperatures. As a result a high oxygen content may be expected. In-depth SIMS analysis with enhanced sensitivity for oxygen was used to analyze SOI layers with thicknesses ranging from 0.5 to 25 μm. Typically a symmetric bump-shaped oxygen profile was obtained. A strong redistribution of oxygen takes place after solidification. SIMS profiles were also obtained of the nitrogen distribution. In samples with a compound capping layer consisting of a thin nitride or oxynitride on top of a thick CVD oxide, significant nitrogen peaks were found at the Si-SiO₂ interfaces immediately after deposition. The peaks increased as the samples were heated and became even more pronounced after ZMR. Different structures in which the nitrogen source was a CVD layer, a NH₃, a NH₃ anneal, or a nitrogen implant were investigated