ION-BEAM SYNTHESIS OF COBALT SILICIDE - EFFECT OF IMPLANTATION TEMPERATURE

In order to understand the physical processes which occur during ion beam synthesis of CoSi2, we have studied the effect of implantation temperature. The experiment consisted of 170 keV Co implantations (dose = 1.7 x 10(17) ions/cm2) in Si(100) targets at temperatures varying between 250-degrees-C and 500-degrees-C. Both as-implanted and annealed samples have been analyzed by several techniques, such as cross-section transmission electron microscopy, X-ray diffraction, Rutherford-backscattering spectrometry and the four-point probe technique. Our data indicate that an optimum implantation temperature interval exists where pinhole-free buried layers of CoSi2 can be synthesized. Outside this interval, the evolution of the precipitate size distribution and/or strain situation in the as-implanted state effectively reduce the necessary depth variation in precipitate stability.