Diffusion of Gallium in Silicon

The diffusion of gallium into silicon has been investigated over a temperature range of 1130°C–1358°C using an open-tube vapor-solid diffusion technique at atmospheric pressure. A p-n junction method combined with incremental conductivity measurements of the diffused layer was used to determine the diffusion constant. Lower diffusivities and a somewhat higher activation energy, (ΔH=95 kcal) were obtained than those reported previously. The difference is attributed to variation of diffusivity with surface concentration and is discussed on the basis of substitutional diffusion proceeding by a vacancy mechanism.