A comprehensive comparison of npn and pnp profile design tradeoffs for SiGe HBTs is conducted using calibrated simulations. The parasitic energy band barrier induced by the SiCe/Si transition in the collector-base space charge region produces very different design constraints for pnp and npn transistors, and they must be optimized separately. A single SiGe profile is found to give acceptable performance for both npn and pnp devices, while still satisfying film stability constraints.