Properties of ZnO/Al2O3 alloy films grown using atomic layer deposition techniques

By varying the ratio of the constituents, compound films can exhibit a widely tunable range of physical properties. Atomic layer deposition (ALD) techniques are based on sequential, self-limiting surface reactions and can grow compound films. In this study, ZnO/Al2O3 alloy films were prepared using ALD techniques. By adjusting the ALD pulse sequence, the ZnO/Al2O3 alloy film composition was varied from 0-100% ZnO. These ZnO/Al2O3 alloy films are expected to display varying properties because ZnO and Al2O3 have very different physical properties. For example, ZnO is a conductor and Al2O3 is an insulator. The physical properties of the ZnO/Al2O3 alloys were explored using a variety of techniques. The growth rate, refractive index, composition, surface roughness, crystallinity, resistivity and density of the ZnO/Al2O3 alloy films could be continuously tuned over the full range of values defined by the pure oxides. The refractive index varied from n = 2.00 for pure ZnO to n = 1.64 for pure Al2O3. The resistivity could be tuned over 18 orders of magnitude from 1022 V cm for pure ZnO to 1016 V cm for pure Al2O3. Anomalies in surface roughness and density vs. Zn content were observed at a Zn content of similar to76%. These anomalies were attributed, in part, to the etching of Zn by Al(CH3)(3) during the ZnO/Al2O3 alloy film growth. (C) 2003 The Electrochemical Society.