Effect of reflector bias voltage on the nanocrystallization of silicon thin films by reactive particle beam assisted chemical vapor deposition

In the present study, the effects of reflector bias voltage on the physical and chemical properties of nanocrystalline silicon deposited by reactive particle beam assisted chemical vapor deposition were systematically studied using various reflector bias voltages. During deposition, the substrate temperature was kept at room temperature. Nanocrystalline Si embedded in an amorphous matrix structure was analyzed by X-ray diffraction and Raman spectroscopy. Films that were deposited under high reflector voltage formed large grains due to largely accumulated internal energy. Using X-ray photoelectron spectroscopy, the chemical state of nanocrystalline silicon was revealed to have only metallic Si bonds. Further, an increase in reflector voltage induced a roughened surface morphology, an increased dark conductivity, and a decreased optical band gap in Si films.