STRUCTURAL-ANALYSIS OF BURIED CONDUCTING COSI2 LAYERS FORMED IN SI BYHIGH-DOSE CO ION-IMPLANTATION

Buried cobalt disilicide layers have been synthesized in Si by high-do se Co+ implantation and annealing. The implanted doses have been 10(17 ) and 3 x 10(17) ions/cm(2), and after implantation the samples have b een annealed in a one (600 degrees C, 1 h) or two step (600 degrees C, 1 h + 1000 degrees C, 30 min) process. The detailed characterization of the samples has been performed by SIMS, XPS, TEM, XRD and Raman sca ttering measurements. The obtained data show the formation of CoSi2 gr ains coherent with the Si lattice at the lowest dose, as well as the f ormation of a continuous CoSi2 epitaxial layer at the highest one. Aft er the two-step anneal, high crystalline quality heteroepitaxial Si/Co Si2/Si structures (10 nm Si/90 nm CoSi2) is obtained for the higher im plantation dose while for the lower one a non-continuous buried layer with octahedral CoSi2 precipitates is formed. (C) 1998 Elsevier Scienc e B.V. All rights reserved.