Two-dimensional modeling of the enhanced diffusion in thin base n-p-n bipolar transistors after lateral ion implantations

Boron diffusion has been simulated in the context of a low thermal budget technology for thin-base integrated bipolar transistors. The simulation was performed using advanced physical models of diffusion, accounting for coupling with point defect diffusion. It has been found that in polysilicon emitter bipolar transistors, where the effect of the emitter implantation has the advantage of being suppressed, the excess point defects generated during the lateral extrinsic base implantations could still induce a nonnegligible broadening of the base and a shrinking of the active region. The influence of such parameters as the type of defects involved and their diffusion coefficient has been investigated