High-concentration in-diffusion of P into both Czochralski-grown and solar grade multicrystalline Si from a spray-on liquid source was studied by using secondary ion mass spectrometry and electrochemical capacitance-voltage profiling (figures 11 and 12). By extracting the concentration-dependent effective diffusivity via the Boltzmann-Matano analysis, an integrated diffusion model based upon previous work was adapted in order to gain some insight into the mechanisms governing such in-diffusion. It was found that, in the tail region of the profiles, diffusion was mediated by interaction with Si self-interstitials, whereas a vacancy mechanism via doubly negative vacancies predominated in the higher concentration region towards the surface, in correspondence with a previous analysis. It was found that both the vacancy and interstitial mechanisms could be described by an Arrhenius behaviour; exhibiting apparent activation energies of 5.2 and 2.1eV, respectively. The results formed the basis for a simplified diffusion simulation, permitting the simulation and subsequent optimization of P diffused emitters in Si solar cells.

High Concentration In-Diffusion of Phosphorus in Si from a Spray-On Source. A.Bentzen, A.Holt, J.S.Christensen, B.G.Svensson: Journal of Applied Physics, 2006, 99[6], 064502 (8pp)