Structural and Optical Features of Nano-Crystalline Silicon Films Prepared by Pecvd and Rf Magnetron Sputter Techniques

Abstract

ABSTRACTNano-crystalline Si films were prepared by plasma enhanced chemical vapor deposition (PECVD) and rf-magnetron sputter techniques at various deposition conditions, and the relations of the photoluminescence (PL) phenomena of the films with process variables are discussed. The phase of the films prepared at R.T. by PECVD techniques is somewhere between amorphous and crystalline states, consisting of nano-crystallites of size ranging from 3.2 to 5.3 nm. These films exhibit significant PL intensities near blue light region; the PL peaks shift from 510 to 460 nm with decreasing the reaction gas (SiH4) fraction from 4.7 to 2.0%. The films prepared at 500 °C by PECVD are composed of about 5 and 150 nm crystallites, exhibiting little PL phenomena. The PL intensity of the films prepared by sputter techniques was observed to increase with raising the sputter power and the post-deposition heat-treatment temperature.