Sol-gel deposited phosphorus and boron doped thin silica films for diffused n super(+)p and n super(+)pp super(+) structures

• Published in: Physica status solidi. C Vol. 11; no. 11-12; pp. 1654 - 1656
• Main Authors: Pene, Armel Duvalier, Hartiti, Bouchaib, Bitjoka, Laurent, Thevenin, Phillippe, Kapseu, Cesar
• Format: Journal Article
• Language: English
• Published: 01.11.2014
• Subjects: Boron; Diffusion; Emittance; Phosphorus; Photovoltaic cells; Silicon; Sol gel process; Solar cells
• ISSN: 1862-6351; 1610-1642
• DOI: 10.1002/pssc.201400060

The realization of a silicon solar cell emitter is a critical and very important step in photovoltaic technology. Indeed, the surface concentration of boron (B) or phosphorus (P) and junction depth determines the photovoltaic conversion efficiency of silicon solar cells. Several techniques are used for the realization of emitters n super(+)p and n super(+)pp super(+) among which the vapor diffusion, ionic implantation and diffusion from solid sources are the most common. This work will be devoted to the realization of emitters made by diffusion of P or B from solid doping sources developed by the sol-gel method associated to spin coating on monocrystalline and polycrystalline silicon wafers. The doping solutions were prepared by sol-gel method using methyltriethoxysilane "MTEOS" or tetramethoxysilane "TEOS" and H sub(4)PO sub(3) or H sub(3)BO sub(3) as precursors. The n super(+) junction was realized by emulsion of phosphoric acid in isopropanol while the p super(+) junction was obtained by emulsion of boric acid H sub(3)BO sub(3) in isopropanol or by diffusion of aluminium at high temperatures. Our samples were annealed at temperatures ranging from 850 to 1000 degree C in a classical furnace under Nitrogen atmosphere. The four point technique has been used to study the electrical properties of n super(+)p and n super(+)pp super(++) structures. The results of measurements showed values of the sheet resistance Rs comparable to those of literature and confirm the diffusion of phosphorus and boron from liquid and solid sources prepared by sol-gel method. ( copyright 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)