Investigation On The Structure And Properties Of Mo-In₂O₃ Films By RF Magnetron Sputtering

Transparent Conductive Oxide (TCO) thin films exhibit very impressive properties, i.e. high electrical conductivity, high transmittance of visible light, high reflectivity of infrared light and other characteristics of semiconductor, and have been used in many fields, such as flat-panel displays, solar cells, sensor of gas, special functional coat. The studies of transparent conductive oxide, like, ZnO, SnO2 and In2O3 have been carried on extensively. In2O3 is a promising candidate to meet the above properties as a TCOs host.Transparent conductive oxide films of In2O3: Mo have been successfully fabricated by using R F magnetron sputtering. The dependence of electrical, optical and structure properties of IMO films on deposition parameters, such as substrate temperature and Mo doping content, have been investigated in detail. XRD and SEM results show that the IMO thin films have good structure. The main research results and analyses as follows:1, From SEM photos of IMO thin films with different substrate and Mo doping content, the surfaces of IMO thin films are smooth and the grains are compact. With the increase of Mo doping content, the grain size increscent.2, The XRD patterns reveal that IMO thin films are polycrystalline with the cube crystal structure and the characteristic line of Mo isn't observed. It proves that the characteristic structure of In2O3 thin film does not change and any new crystal structure doesn't form after Mo doping. In the research, the dependence of crystal structure and grain sizes on doping content is not obvious. At 350℃, IMO thin films have strongly preferred orientation of (222).3, At 350℃substrate temperature and 2.5x2.5mm2 Mo, the films with minimum resistivity of 1.53×10-3Ω·cm was obtained. The highest carrier mobility is 23.2 cm2V-1s-1, while the carrier concentration is 2.10×1015cm-3, and the average transmittance is about 80% in the visible light region. The widening of optical band gap was mainly determined by the Burstein-Moss effect.4, The results show that substrate temperature greatly effects on the optical and electrical characterization of the IMO thin films. Molybdenum dopant and substrate temperature are the dominant factors to enhance the conductivity. At the higher substrate temperature and the appropriate process parameters (deposition pressure, argon gas flow and sputtering power), the sputtered particles were deposited on the substrate surface energy, and get better IMO crystalline film, which has a high visible light through rate.5, Based on the above analysis of the mechanism of this systems, we regarded thin films may have magnetic properties.The In2O3 films are diamagnetic, and the curves of the M-H testing at room temperature show that IMO exhibited week ferromagnetism at room temperature. It's revealed that the magnetic of film samples have enhanced the trend with increasing the dopant Mo concentration and higher substrate temperature.