Boron Segregation and Out-diffusion in Single-Crystal Si 1-y C y

Abstract

AbstractBoron segregation and its effect on carbon diffusion is studied in single-crystal Si1-yCy. We find that boron segregates from silicon to Si0.996C0.004 at a level m=[B]SiC/[B]Si = 1.7 during a 2 hour, 850°Cannealin N2. After this anneal, if most of the carbon is then removed from the Si1-yCy layer (via an oxidation-enhanced out-diffusion process), most of the boron segregation is removed as well. This argues against immobile B-C defects as the predominant mechanism driving the segregation. Boron is shown to increase carbon diffusion during the N2 anneal, but also appears to enhance carbon precipitation during a subsequent oxidation.