Properties of TiC thin films grown by pulsed laser deposition

Titanium carbide thin films have been deposited on both (100) silicon and f used silica substrates by pulsed laser ablating a polycrystalline TiC targe t. At a KrF excimer laser intensity of about 8 x 10(8) W/cm(2), the pulsed laser deposition (PLD) of TiC films was investigated at substrate depositio n temperatures ranging from 25 to 600 degrees C. The structure, surface com position, electrical resistivity, stress, work function and morphology of t he PLD TiC films were characterized as a function of the deposition tempera ture. While all the deposited TiC films are polycrystalline with a preferre d (111) orientation, both the magnitude of their compressive stress and the ir resistivity were found to decrease gradually as a function of the deposi tion temperature, from -7 to similar to-3 GPa and from 140 to 80 mu Omega c m, respectively. The X-ray photoelectron spectroscopy (XPS) analysis reveal ed that oxygen (at an average level of similar to 10 at.%) is incorporated into the TiC films where it substitutes for C. The surface composition of t he films is found to be stoichiometric with an average Ti/(C + O) ratio of 0.98 +/- 0.06. The deposited TiC films exhibited low work functions in the (3.74-3.94) eV range. Their surface morphology is characterized by a very s mooth surface on which some particulates are present. The density of these particulates (of which typical lateral dimension is about 1 mu m and height is about 100 nm) is of the order of 2 per 100 mu m(2). The properties of t hese PLD TiC films are discussed in view of their use as electron injecting electrode materials for organic electroluminescent devices. (C) 1999 Elsev ier Science B.V. All rights reserved.