Cross-sectional TEM investigations of the influence of P+ ions implanted in the Si substrate on the atomic interdiffusion in the Cr-Si system

Cross-sectional transmission electron microscopy was used to study the effe ct of doped silicon substrate on the formation of CrSi2 disilicide. A chrom ium film 800 Angstrom thick was electron gun deposited onto unimplanted and phosphorus implanted Si(111) substrates. The implanted dose was 5 x 10(15) at. cm(-2) at 30 keV. The Cr-Si samples were heat treated in vacuum at 475 degrees C for different times. Transmission electron microscopy investigat ions, performed on doped and undoped Si substrates, have shown that the pre sence of P+ ions resulted in the delay of the CrSi2 compound growth. In add ition, the nanoanalysis of the samples with P+ implanted silicon has reveal ed the apparition of a crystalline Si-Cr alloy in the Si substrate near the CrSi2-Si interface, the formation of an amorphous Si thin layer between th e formed silicide and this alloy, and a diffusion of Si atoms towards the f ree surface. (C) 2000 Elsevier Science S.A. All rights reserved.