INTER-ELECTRODE SEPARATION INDUCED AMORPHOUS-TO-NANOCRYSTALLINE TRANSITION OF HYDROGENATED SILICON PREPARED BY CAPACITIVELY COUPLED RF PE-CVD TECHNIQUE

Role of inter-electrode spacing in capacitively coupled radio frequency plasma enhanced chemical vapor deposition deposition (PE-CVD) system was studied. The influence of inter-electrode separation on the structural, optical and electrical properties of the deposited films was carefully invesigated keeping all other deposition parameters constant. The results indicate that the film growth rate critically depends up on the plasma chemistry/gas phase chemistry altered by variation of interelectrode separation. Structure and optical properties are strongly influenced by interelectrode separation. The nanocrystallization in the material was observed for smaller inter-electrode separation, whereas higher inter-electrode separation favors amorphous structure of the deposited material. The band gap of the material was found to decrease from similar to 2 eV to 1.8 eV when inter-electrode separation was varied from 15 mm to 40 mm.