Ion microscope investigations of non-uniform surfaces of thin SiO2 films produced by high-temperature nitridation experiments

Elemental composition and surface changes of thin high-temperature nitrided SiO2 films were studied with ion microscopy using 0.92 and 1.4 MeV deuteri um ions. Surprisingly, a non-uniform artificial pattern on the surface of s amples annealed above 1150 degreesC was observed. Nuclear reaction micropro be analysis and scanning electron microscopy were applied to reveal the ori gin and composition of the pattern. The surface topology and the maps of th e light elements were studied. The backscattered signals in the NRA data pr ovided maps of Si and variations in the elemental compositions at the surfa ce of the specimens. With both techniques, significant differences in the e lemental make-up within the pattern were obtained. The light elements were found to be enriched differently in the centre of the nonuniform patterns a nd the surrounding ring-like structures, suggesting the formation of compou nds of C, N, O and Si. (C) 2001 Elsevier Science B.V. All rights reserved.