The diffusion behavior of arsenic in polycrystalline silicon (polyhyphen;Si) and the grain growth of arsenichyphen;doped polyhyphen;Si with a TiSi2overlying layer were investigated by MeV4He2+backscattering techniques and transmission electron microscopy. Finehyphen;grain (30ndash;40 nm) polyhyphen;Si was implanted with 1 or 3times;1016arsenic ions/cm2and annealed in two stages: (1) at 885 or 985thinsp;deg;C in an oxygen atmosphere to distribute (homogenize) the arsenic throughout the polyhyphen;Si layer and (2) at 750thinsp;deg;C in a vacuum ambient with deposited Ti or TiSi2overlay to determine the outhyphen;diffusion of arsenic. After a 750thinsp;deg;C anneal for 8 h, there was essentially no arsenic redistribution in the sample homogenized at 985thinsp;deg;C, but a loss of 40percnt; arsenic was observed in the sample homogenized at 885thinsp;deg;C. The Si grains in the 280hyphen;nmhyphen;thick polyhyphen;Si layer grew in size during homogenization, up to 400 nm at 985thinsp;deg;C and 150 nm at 885thinsp;deg;C. No grain growth was observed after a 750thinsp;deg;C, 8hyphen;h anneal of doped polyhyphen;Si films in contact with Ti.
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