Reactive sputtering of amorphous In-Zn-O TCO from metallic targets

Amorphous In-Zn-O (a-IZO) transparent conducting oxides with conductivity σ ≈ 3000 S/cm can be sputter deposited at ambient temperature, are damp-heat resistant and have been demonstrated to work well as transparent contacts for CIGS PV and Epi-Si PV. However, the high cost of ceramic In-Zn-O sputter targets has limited the widespread use of a-IZO TCOs in PV. Here, we demonstrate a new process that results in conductive and transparent a-InZnO thin films deposited via reactive sputtering from a metallic In-Zn alloy target. The highest conductivity obtained to date, σ ≈ 2100 S/cm, is an order of magnitude higher than the previous best literature result for reactively sputtered a-InZnO.