High Purity Titanium Silicide Films Formed by Sputter Deposition and Rapid Thermal Annealing

We have investigated the formation of titanium silicide films sputter deposited from a high purity (99.995%) composite TiSi2.2 target. The films, sputtered at a rate of 3.7 nm/sec, were deposited on Si(100), Si02 , and N+ Poly-Si substrates at temperatures ranging from room temperature to 425°C. Room temperature depositions produced amorphous films, while heated substrate depositions formed crystalline films with a metastable C49 TiSi2 structure. Rapid thermal processing of these films at temperatures higher than 700°C resulted in the formation of a stable C54 TiSi2 structure. Stoichiometry of the deposited films over a 10 cm diameter wafer was found to be independent of the substrate temperature. Stress in the films was measured as a function of deposition and annealing parameters. The amorphous films showed a tensile stress of about 0.1 GPa, while films deposited on substrates at 425°C had an order of magnitude higher tensile stress level.The resistivity measured on the 400°C deposited films was about half of that obtained with the films deposited at roomtemperature. A comparison between films deposited on a hot substrate and those which were rapid thermal processed is presented.