Atomic layer deposited zinc tin oxide channel for amorphous oxide thin film transistors

Bottom-gate thin film transistors with amorphous zinc tin oxide channels were grown by atomic layer deposition (ALD). The films maintained their amorphous character up to temperatures over 500 \\(\∘\\)C. The highest field effect mobility was ~13 \\(cm^2/V^.s\\) with on-to-off ratios of drain current ~10\\(^9\\)-10\\(¹⁰\\). The lowest subthreshold swing of 0.27 V/decade was observed with thermal oxide as a gate insulator. The channel layers grown at 170 \\(\∘\\)C showed better transistor properties than those grown at 120 \\(\∘\\)C. Channels with higher zinc to tin ratio (~3-4) also performed better than ones with lower ratios (~1-3).