Densification and resistance of Ta 2 O 5 and ZnO co-doped SnO 2 ceramic targets for low-cost TCO films of solar cells

Abstract

Low cost transparent and conducting oxide (TCO) films are important for solar cells, and sintering densification of SnO₂-based ceramic targets for depositing TCO film are difficult. Ta₂O₅ and ZnO were used as dopants and harmless sintering aid, respectively. The targets with different ZnO contents show single rutile structure. The sintering densification was improved by ZnO, and the dense microstructure has fine grains with an average size of 0.2-3 µm. The decomposition and volatilization of targets sintered at higher temperature decrease density. The 0.85 wt% ZnO doped target at the optimal sintering temperature of 1500°C obtain the highest relative density (> 99%) and low resistance (< 50 Ω). The enhanced density of SnO₂-based targets by ZnO can effectively improve the density, and further inhibit the formation of nodules on the target surface during magnetron sputtering.