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Received Nov 17, 2017; Accepted Jan 9, 2018
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1. Introduction
The transparent conductive oxide films (TCO) had excellent physical and chemical properties, and the coating process parameters have significant influence on the optical, electrical, and structural properties and residual stress of the transparent conductive oxide films. Indium tin oxide (ITO) thin film is one kind of transparent conductive films. Due to its high transmittance and good physical and chemical properties [1, 2], it is widely used in optical devices like flat panel displays, solar cells, sensors, and so on [3–5]. There are many different methods for the fabrication of ITO thin films including the magnetron sputtering method [6, 7], thermal evaporation method [8], plasma ion-assisted evaporation [9], reactive electron-beam evaporation [10], and sol-gel method [11]. It is well known that almost all thin films, produced by the various deposition techniques, have residual stresses. Residual stress that develops during thin film growth is critical issue for many applications. Films stress causes many undesirable phenomena, for example, the cracking or peeling of the film and the bending of the substrate. The precise measurement of residual stress in thin films is helpful to understand the stress behaviour and related effects. DC magnetron sputter deposition has generally been used in industrial production lines for the deposition of ITO films because this method yields homogeneous ITO films with low resistivity and good reproducibility. Therefore, in order to improve the quality of the ITO thin films, the surface characteristics, residual stresses, and optical and electrical properties of DC magnetron sputtering ITO thin films have been investigated experimentally.
There are many papers to explore the optical, electrical, and structural properties of ITO thin films prepared by different deposition methods. However, there are few studies to report the effect of oxygen flow rate on the residual stress and surface roughness of sputtering ITO thin films [12–14]. This study investigated the effect of oxygen flow rate on optical, mechanical, and electrical properties and the surface roughness of ITO thin films prepared by DC magnetron sputtering technique. The optical transmittance spectra of ITO films were...