Growth peculiarities of silicon nanoparticles in an oxide matrix prepared by magnetron sputtering

The process of thermal decomposition of SiO_x layers prepared by magnetron sputtering is studied by photoluminescence, AFM, Auger and SIMS methods. The dependence of the depth distribution of the chemical composition on excess silicon content is obtained. It is shown that as-sputtered SiO _x layers are characterized by homogeneous enough chemical composition and do not exhibit photoluminescence. Hightemperature annealing in nitrogen atmosphere stimulates not only Si nanoparticle formation but also the appearance of a Si depleted region near layer-substrate interface. This last process is found to be dependent on excess Si content. The decrease of silicon content in the depth of the annealed layers is accompanied by the decrease of Si particle sizes as proved by the blue shift of the photoluminescence maximum. The mechanisms of SiO_x decomposition and possible reasons for the appearance of the Si depleted region are discussed.