Physicochemical and structural properties of ultra thin films with embedded silicon particles

This work is devoted to the study of nanostructured silicon thin films which were deposited by a pulsed plasma enhanced chemical vapour deposition process using SiH4/N2O/He mixture. According to the elemental XPS analysis and IR spectroscopy, the as-deposited films were contained silicon, oxygen, nitrogen and bonded hydrogen. The film composition was been controlled by varying the substrate temperature and the plasma pulsation. As a consequence, the increase in the substrate temperature showed evident separation of the two phases: hydrogenated amorphous silicon and silicon oxide with nitrogen impurities. The employment of the square-wave modulated discharges leads to a spectacular improvement of the Si particle size decrease.