Critical assessment of the Si-P system: P solubility in the Si-rich region and refining by phosphorus distillation

The P-Si system has been studied due to its poisonous importance in silicon electronic devices for photovoltaic applications. Thermodynamic and phase diagram data of the Si-P system available in literature are critically evaluated for further optimization of thermodynamic properties in order to improve the thermodynamic description of this system, especially in the Si-rich region. After revising the solubility data of P in solid Si in the Si-rich region its upper limit is now evaluated at 1w% P (mole fraction X_P ≈ 0.0095). With this controversial solubility limit resolved, current modelling of the liquid and solid phases is described more accurately. Distillation capacity of phosphorus by vaporization is then assessed for liquid and solid silicon on the basis of the determination of the infinite dilution activity coefficient of phosphorus in silicon - the Henry's coefficient - as well as numerous gaseous species existing in the Si-P binary system. The lack of original calorimetric data is highlighted in view to a further more reliable description of the complete Si-P system.