A self-aligned double poly-Si process using nonselective epitaxy of SiGe:C for the intrinsic base and a dual stack of poly-Si and poly-SiGe for the extrinsic base is presented. Self-alignment of the extrinsic base is obtained by detailed control of the emitter window etch procedure. The etch of the extrinsic base is endpointed at the poly-Si/poly-SiGe interface, and is followed by a timed etch of the SiGe film. Due to the selectivity towards Si, the etch can be stopped at the epitaxial Si surface.The SiGe:C epitaxy is obtained using ultra-high vacuum chemical vapor deposition (UHV/CVD). As a result of the slightly higher growth rate of the epitaxial film compared to the polycrystalline material, an almost planar surface could be obtained.Working devices have been verified by electrical measurements.