Diffusion and electrical properties of 3d transition-metal impurities in silicon

The characterization of diffusion and electrical properties of 3d transition metal (3dTM) impurities in silicon are very important because they can be easily introduced to silicon crystals during heat treatment and give rise to detrimental effects on silicon devices. As st result of fast interstitial diffusion, they easily precipitate or react with other defects to form complexes during cooling or the heat treatment at high temperatures. Interstitial atoms from titanium to iron and copper in silicon are electrically active, and introduce multilevels within the band gap of silicon. The present paper describes a survey on the diffusion and electrical properties of titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper in silicon. Among 3dTM elements, nickel and cobalt have the peculiar nature that while the majority species are the interstitial atoms, only the minority substitutional atoms are electrically active. Diffusion and electrical properties of nickel are described in the combination with the recent experimental results. The present paper outlines the results of comprehensive studies of iron in n-type silicon grown by the floating-zone and Czochralski methods.