Effect of substrate temperature on the bonded states of indium tin oxide thin films deposited by plasma enhanced chemical vapor deposition

Indium tin oxide (ITO) thin films were deposited on Si(100) substrates using plasma enhanced chemical vapor deposition technique. The metal-organic sources used in this study were Tris (2,2,6,6-tetramethyl-3,5-heptanedionato) indium(III) and tin(III) acetate of 99.9% purity, which are readily available. The deposition of ITO films was carried out for I h at different reaction temperatures (200, 250, 300 and 350 degreesC), with oxygen as reaction gas (20 sccm) and argon as carrier gas (200 sccm). The deposited films were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The minimum sheet resistance, measured using a four-probe method, was 2500 Ohmcm(-2) at a deposition temperature of 300 degreesC. XRD analysis shows a structural change and a highly textured film with (100) preferred orientation with increasing deposition temperature. Growth rate, estimated from SEM images of the deposited film was similar to10(10) cm(-2) h(-1). It was observed from XPS results that oxygen atoms were bonded to In and Sn atoms indicating formation of ITO compound (bonded states of In2O3). It is also seen that all the examined ITO film contains amorphous and crystalline phases. (C) 2003 Elsevier Science B.V. All rights reserved.