Microstructure and resistivity of ITO targets sintered by cold and microwave sintering for solar cell applications

High mobility of ITO films for solar cells is enhanced by decreasing SnO 2 content in ITO gargets. However, the sintering densification of ITO targets becomes difficult. The density of ITO targets with low SnO 2 content is enhanced by TiO 2 , SiO 2 and cold sintering. The green bodies of ITO are first compacted by cold sintering and then further fully densified by microwave sintering. Three types of ITO targets exhibit single cubic bixbyite structure, dense microstructure and transgranular fracture. ITO targets sintered at a microwave temperature of 1450 °C have a high relative density of over 99% and low resistivity of below 4.87 × 10 −4 Ω·cm. The fine grains have a size of less than 2.0 μm. Therefore, the synergistic effect of additives and the sintering process can resolve the difficulty of sintering densification of ITO targets with low doping content.