Zinc tin oxide thin-film transistors via reactive sputtering using a metal target

Abstract

Zinc tin oxide based thin-film transistors are fabricated via reactive magnetron sputtering using a metallic zinc/tin alloy target. The oxygen partial pressure and total sputtering pressure are explored. An oxygen partial pressure and total sputtering pressure of 0.8 and $30\mathrm{mTorr}$ , respectively, are found to be optimal. Devices with a reactively sputtered zinc tin oxide channel layer and channel layer annealing of $500°\mathrm{C}$ exhibit incremental mobilities of $\sim 32{\mathrm{cm}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$ , turn-on voltage of $\sim -4\mathrm{V}$ and drain current on-to-off ratios of $\sim {10}^7$ . Both direct current and radio frequency magnetron sputtering are explored showing similar characteristics.