Characterization of lateral dopant diffusion in silicides

The lateral diffusion of dopants in silicides has been studied using a sensitive Schottky barrier test structure that relies on changes in the I-V characteristics of silicide/silicon interfaces due to dopant diffusion from a doped silicide into silicon. The test structure has been used to determine the diffusivity of As and B in WSi/sub 2/ and TiSi/sub 2/. The diffusion process is modeled as a 1-D diffusion from a constant concentration dopant source. The diffusivity of B and As in WSi/sub 2/ is found to be 1.0*10/sup -3/ exp (-1.17/kT) cm/sup 2//s and 2.6 exp (-2.11/kT) cm/sup 2//s, respectively. The diffusivity of As in TiSi/sub 2/ is 4.8 exp (-2.13/kT) cm/sup 2//s. No measurable lateral diffusion of B in TiSi/sub 2/ has been observed.<
>