Journal of the Less-Common Metals, 52 (1977) 29 - 36 0 Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands 29 CHEMICAL VAPOR DEPOSITION OF TANTALUM NITRIDE FILMS TAKEHIKO TAKAHASHI, HIDEAKl ITOH and SHIROH OZEKI Department of Applied Chemistry, Faculty of Engineering, Nagoya University, Nagoya 464 (Japan) (Received June 19,1976) Summary Using a gaseous mixture of TaCl,, Ns, Ha and Ar the growth of tantalum nitride films by vapor phase reaction was investigated. An isotropic polycrys- talline film of TaN or TasN of thickness up to 10 pm was grown on a (100) silicon substrate in the temperature range 700 - 1000 ‘C, the maximum weight of deposit being obtained at 850 “C!. The optimum gas flow rate and composition to give an adherent and uniform film of TaN were: Ha flow rate 4 - 6 ml s ‘, N,:TaC15 mole ratio 70 - 120. The tantalum nitride film was found to be chemically stable in oxygen (20 mol.%) and chlorine (1.0 mol.%) up to temperatures of 650 “C and 450 ‘C, respectively. The Vickers micro- hardness of as-grown films ranged from 1200 to 2200 depending on the de- position temperature and the nitrogen flow rate. 1. Introduction Tantalum nitride (TaN) has a melting point of 3090 “C and shows a relatively high chemical stability [l] at high temperatures. This compound has been recognized not only as a refractory material which is resistant to corrosion but also as an electronic circuit material. According to recent studies [2 - 41 tantalum nitride has a low TCR (temperature coefficient of resistance) and this makes it suitable for application as a film resistor. Tantalum nitride of submicron thickness has previously been vapor deposited onto various substrates, usually by reactive evaporation or reactive sputtering [5 - 81. The detailed study of thicker films of tantalum nitride formed by chemical vapor deposition (CVD), however, has received little attention although the thermal nitriding of tantalum metal [9 - lo] and the formation of tantalum nitride by plasma spraying have been investigated. Hieber [ll] recently obtained thin films of Ta, TaaN, TaN (f.c.c.) and TaaNb by CVD on fused silica glass and measured their electrical properties. The results were similar to those reported for sputtered films. The present study is concerned with the formation of a thick tantalum nitride film on a silicon single crystal from a gaseous mixture of TaC15, Na,