TIME-RESOLVED X-RAY DIFFRACTION STUDIES OF THE TEXTURE FORMATION KINETICS IN THE C49-C54 TiSi 2 PHASE TRANSFORMATION A. S. Özcan 1 , K. F. Ludwig, Jr. 1 , C. Lavoie 2 , C. Cabral, Jr. 2 , J. M. E. Harper 2 1 Boston University, Physics Department, Boston, MA 02215 2 IBM T.J. Watson Research Center, Yorktown Heights, NY 10598 ABSTRACT The transformation from the C49 to the C54 phase in TiSi 2 thin films has been studied for more than a decade because of its importance to the semiconductor industry. In previous work we identified three dominant C54 orientations in TiSi 2 thin films on Si(001) substrates using X-ray pole figure analysis. In the current study the evolution of the three prominent C54 texture components was further examined using synchrotron based time-resolved in-situ X-ray diffraction. These experiments utilized an annealing chamber with a hemispherical beryllium window mounted on a four-circle diffractometer and a CCD area detector, which made it possible to observe the development of the complicated C54 texturing. The results on the formation kinetics show significant differences in the growth of the individual orientations. Simulations suggest that this could be explained by an inhomogeneous nucleation of different texture components in the thin film, but not by simple differences in nucleation and/or growth rates. Classical Johnson-Mehl-Avrami-Kolmogorov (JMAK) analysis of nucleation and growth was applied to model the C49-C54 phase transformation kinetics for each C54 orientation. These results showed a systematic decrease of the Avrami exponent, n, from 3 to 2 with increasing annealing temperature. Within a JMAK approach this could be explained by the presence of a limited number of C54 nucleation sites coupled with a faster increase in nucleation rate than in growth velocity with increasing anneal temperature. INTRODUCTION The transformation from the C49 to the C54 phase in TiSi 2 thin films has been studied extensively due the technological interest in the material [1,2]. TiSi 2 is widely used as a contact and a local interconnect in integrated circuits. Thin film TiSi 2 exists in two crystallographic structures, namely the C49 and the C54 phases. Upon annealing Ti on Si, the first disilicide phase to form is usually the C49 phase and a subsequent anneal is needed to transform the film into the C54 structure. The utilization of TiSi 2 in integrated circuits requires complete transformation into the low resistance C54 phase. However, the transformation into the C54 phase can be difficult, especially in submicron structures, due to the low density of nucleation. Despite previous efforts, the physical mechanisms behind the C49-C54 transformation are not completely understood. We believe that understanding texture formation will provide important insights into the transformation process. In an earlier study we have identified the dominant preferred C54 orientations in thin films on Si(001) substrates using pole figure analysis [3]. Figure 1 shows a typical (311) pole figure from the C54 phase grown from sputtered Ti. Although the pole figure shows that the texturing in the Copyright©JCPDS - International Centre for Diffraction Data 2003, Advances in X-ray Analysis, Volume 46. 157