IMPACT OF METALLIZATIO TECHIQUES O SURFACE PASSIVATIO OF HIGH EFFICIECY CRYSTALLIE SILICO SOLAR CELLS

摘要

Most of the high-efficiency c-Si solar cells are based on dielectric films that electrically passivate c-Sisurface and must keep their passivation properties after metal deposition on top of them. This work studies the impactof three different aluminum Physical Vapor Deposition (PVD) methods (thermal, e-beam, sputtering) on the c-Sisurface passivation provided by SiO2 and Al2O3 films. Effective surface recombination vel°City is measured beforeand after metal deposition. Results show that e-beam and sputtering techniques degrade surface passivation whilethermal evaporation has no impact. Surface passivation can be recovered and even improved by means of anannealing with the aluminum film on top of the dielectric leading to the so-called alnealing. Additionally, after thisalnealing Capacitance-Voltage measurements and lifetime spectroscopy analysis suggest a strong dependence offixed charge density for SiO2 films on the metal deposition technique that helps in c-Si surface passivation.