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

Abstract

Cross-sectional transmission electron microscopy was used to study the effect of doped silicon substrate on the formation of CrSi 2 disilicide. A chromium film 800 Å thick was electron gun deposited onto unimplanted and phosphorus implanted Si(111) substrates. The implanted dose was 5×10 15 at. cm −2 at 30 keV. The Cr–Si samples were heat treated in vacuum at 475°C for different times. Transmission electron microscopy investigations, performed on doped and undoped Si substrates, have shown that the presence of P + ions resulted in the delay of the CrSi 2 compound growth. In addition, the nanoanalysis of the samples with P + implanted silicon has revealed the apparition of a crystalline Si–Cr alloy in the Si substrate near the CrSi 2–Si interface, the formation of an amorphous Si thin layer between the formed silicide and this alloy, and a diffusion of Si atoms towards the free surface.