Indium Oxide Thin Films by Atomic Layer Deposition Using Trimethylindium and Ozone

Abstract

We investigated the atomic layer deposition (ALD) of indium oxide (In2O3) thin films using alternating exposures of trimethylindium (TMIn) and a variety of oxygen sources: ozone (O3), O2, deionized H2O, and hydrogen peroxide (H2O2). We used in situ quartz crystal microbalance measurements to evaluate the effectiveness of the different oxygen sources and found that only O3 yielded viable and sustained In2O3 growth with TMIn. These measurements also provided details about the In2O3 growth mechanism and enabled us to verify that both the TMIn and O3 surface reactions were self-limiting. In2O3 thin films were prepared and characterized using X-ray diffraction, ultraviolet–visible spectrophotometry, spectroscopic ellipsometry, X-ray photoelectron spectroscopy, and scanning electron microscopy. The electrical transport properties of these layers were studied by Hall probe measurements. We found that, at deposition temperatures within the range of 100–200 °C, the In2O3 growth per cycle was nearly constant at 0.4...