Two dimensional simulation of transient enhanced boron out-diffusion from the base of a SiGe HBT due to an extrinsic base implant

The effects of an extrinsic base implant in SiGe HBTs are investigated using two dimensional process and device simulation and measurements of collector current as a function of temperature. Point defects generated by the implant are shown to give rise to transient enhanced boron diffusion from the SiGe base around the emitter perimeter, which causes a geometry-dependent collector current. Methods for suppressing these effects are investigated.