Atomic layer deposition of indium oxide thin film from a liquid indium complex containing 1-dimethylamino-2-methyl-2-propoxy ligands

Abstract

In2O3 thin films were grown from a newly developed, liquid, homoleptic, In-based complex, tris(1-dimethylamino-2-methyl-2-propoxy)indium [In(dmamp)3], and O3 by atomic layer deposition (ALD) at growth temperatures of 150–200°C. In(dmamp)3 exhibited single-step evaporation with negligible residue and excellent thermal stability between 30 and 250°C. The self-limiting surface reaction of In2O3 during ALD was demonstrated by varying the In(dmamp)3 and O3 pulse lengths, with a growth rate of 0.027nm/cycle achieved at 200°C. The In2O3 films grown at temperatures over 175°C exhibited negligible concentrations of impurities, whereas that grown below 175°C had concentrations of residual C of 6–8 at.%. Glancing angle X-ray diffraction revealed that the In2O3 films were polycrystalline in nature when the deposition temperature was greater than 200°C. The In2O3 films grown at 150–200°C exhibited carrier concentrations of 1.5×1018–6.6×1019cm−3, resistivities of 15.1–2×10−3Ωcm, and Hall mobilities of 0.8–42cm2/(Vs).