A heat-dissipation packaging structure, with graphene plated-heat-sink (PHS) layer, of GaInP/GaAs collector-up HBTs has been designed and evaluated by finite-element modeling technique. Based on 2-D and 3-D systematic analyses, it is indicated that the reported configuration can be further minimized by 34%. Consequently, thinning the thermal via constructed underneath the GaInP/GaAs collector-up HBT should be effective for the shrinkage of heat-dissipation packaging configurations, and the proposed approach has been demonstrated to be useful for optimizing HBT-based amplifiers in future mobile communication systems.