Simulation of nucleation and growth of atomic layer deposition phosphorus for doping of advanced FinFETs

Simulations for the nucleation and growth of phosphorus films were carried out using density functional theory. The surface was represented by a Si9H12 truncated cluster surface model with 2 × 1-reconstructured (100) Si-OH terminations for the initial reaction sites. Chemistries included phosphorous halides (PF3, PCl3, and PBr3) and disilane (Si2H6). Atomic layer deposition (ALD) reaction sequences were illustrated with three-dimensional molecular models using sequential PF3 and Si2H6 reactions and featuring SiFH3 as a byproduct. Exothermic reaction pathways were developed for both nucleation and growth for a Si-OH surface. Energetically favorable reactions for the deposition of four phosphorus atoms including lateral P–P bonding were simulated. This paper suggests energetically favorable thermodynamic reactions for the growth of elemental phosphorus on (100) silicon. Phosphorus layers made by ALD are an option for doping advanced fin field-effect transistors (FinFETs). Phosphorus may be thermally diffuse...