Low defect density amorphous hydrogenated silicon prepared by homogeneous chemical vapor deposition

Abstract

Compositional, structural and transport data are presented for amorphous hydrogenated silicon (a-Si:H) prepared by homogeneous chemical vapor deposition (HOMOCVD). We find a remarkable similarity in properties between HOMOCVD and plasma a-Si:H, including a nearly identical range (250-300°C) for the preparation of highly photoconductive films. However, unlike plasma material, HOMOCVD a-Si:H exhibits negligible photo-induced instabilities (Staebler-Wronski effect) and low spin concentrations over a wide span of deposition conditions. These results indicate that a significant defect-creating reaction, most likely surface Si-H bond scission, is occurring in the plasma environment, but absent in HOMOCVD.