Contacts realization by rapid thermal annealing in multicrystalline silicon solar cells with special emphasis on metal influence

To improve the quality of solar cell screen printed contacts, the authors have previously shown the capability to sinter the screen printed contacts by rapid thermal annealing (RTA) instead of commercial sintering; they have also noticed that the commonly used TiO₂ coating deposited by spray enhances the quality of the contact either with classical annealing or RTA. The aim of the present work is to analyse the metal influence on either front or back contacts realization by RTA on Polix p type multicrystalline silicon subsequently phosphorus diffused. The screen printed contact was replaced by the chosen metal dot obtained by evaporation. The authors have studied: Al/TiO₂; Ag/Al/TiO₂; Cu/Al/TiO₂; Pt/Al/TiO₂ and Cu/Cr/TiO₂. The RTA treatments were carried out at various temperatures and annealing time in an Ar ambience. The quality of the contacts are analysed from I-V characteristics, and possible diffusions of metallic species are characterized by SIMS experiments