Test structure for characterization of polycrystalline silicon as a diffusion source for advanced devices

Test structures designed for measuring diffusion of impurities in both lateral and vertical directions in deposited films are described. The impact of predeposition cleans on the diffusion of impurities across film-film and film-substrate interfaces can be investigated. Although the structures are designed for studying diffusion in polycrystalline silicon, the basic idea could be applied to other films. A general description of the test structures is given, and results obtained for the lateral diffusion of arsenic in polycrystalline silicon are presented. From these results, the effective lateral diffusion coefficient for arsenic in polycrystalline silicon is determined to be 1.410 exp(-2.63/kT)(cm/sup 2//s).<>