Effects of Phosphorus Doping and Postgrowth Laser Annealing on the Structural, Electrical, and Chemical Properties of Phosphorus-Doped Silicon Films

Abstract

Phosphorus has low solubility in silicon, but nonequilibrium incorporation of phosphorus exhibits unusual high strain and low contact resistance for advanced Si-based metal-oxide-semiconductor field-effect transistors. Despite recent technological breakthroughs, the origin of tensile strain and electrical deactivation in P-doped Si films is not yet fully understood. Here, by using a combination of experiments and first-principles calculations, we investigate the effect of nonequilibrium phosphorus incorporation into Si lattices and subsequent annealing on structural, electrical, and bonding properties of P-doped Si films. Quantitative structural analyses reveal that the high tensile strain is generated by the incorporation of P into Si substitutional sites irrespective of the distribution of P atoms. More importantly, we found that advanced postgrowth annealing lead to significantly enhanced electrical properties while keeping the same physical states without loss of induced strain. To explore the reason ...