INTERFACIAL REACTION AND FORMATION MECHANISM OF EPITAXIAL COSI2 BY RAPID THERMAL ANNEALING IN CO TI/SI(100) SYSTEM/

A ternary compound of Co3Ti2Si is suggested as a reaction barrier for the formation of epitaxial CoSi2 in the Co/Ti/Si system when adopting the rapid thermal annealing process. It controls Co diffusion to the S i substrate, followed by formation of epitaxial CoSi2. After the epita xial CoSi2 was formed, the interfacial morphology of the upper layer/C oSi2 interface was very different according to silicidation temperatur e, that is, the interface was planar at 800 degrees C, but rough at 90 0 degrees C. This was attributed to the reaction between the upper lay er consisting of Co-Ti-Si and the CoSi2 layer at 900 degrees C, which resulted in Ti-rich precipitates at the surface. The Ti-rich precipita tes acted as a diffusion sink of dopant, thus, the leakage current den sity for the silicidation temperature of 900 degrees C was much higher than that for the temperature of 800 degrees C. These results suggest that the silicidation temperature is one of the most critical factors in determining the leakage current of the p(+)n junction diode. (C) 1 997 American Institute of Physics.