As device scaling for high-performance bipolar transistors continues, not only the vertical scaling but also the lateral scaling with reduction of the parasitics can have an important impact on the reliability of the HBT. In this work we will present the impact on the RF performance and the reliability of the vertical and lateral scaling of a SiGe:C HBT with a low-complexity QSA (quasi self-aligned) architecture. The reliability will be assessed for three different stress modes. (c) 2005 Elsevier B.V. All rights reserved.