Diffusion of Phosphorus in Silicon Thin Films by Spin and Dip Coating

Abstract

In this work, Spin coating and Dip coating techniques are used for the diffusion of phosphorus in silicon in order to realize the emitter of a silicon solar cell which is a very important and critical step in photovoltaic technology. Several techniques are used for the realization of n+p junctions among which the ionic implantation, vapor phase diffusion and diffusion from solid sources are the most common. In this work, the emitter is made by diffusion of solid doping sources that we elaborated by the sol gel method associated with spin coating and dip coating on silicon wafers. The doping solutions were prepared by the sol gel method using tetraethoxysilane "TEOS" and methyltriethoxysilane "MTEOS" and phosphoric acid H3PO4 as a precursor by emulsion of phosphoric acid in isopropanol. This experience allowed us to study the electrical properties of the emitters using the four-point technique. The measurement results showed that the values of the sheet resistance R□ obtained by dip coating are comparable to those obtained with the spin coating technique.