In this manuscript, the compact potential model for double-gate (DG) Si1-xGex/Si heterojunction tunnel field-effect transistors (TFETs) is proposed by adopting several strategies to the previous model. Compared with the control model, the enhanced model can describe the effects of additional parameters such as electron permittivity and Si1-xGex affinity, doping dependent bandgap narrowing, temperature, built-in potential change due to degenerately doping condition and energy band off-sets. The model accuracy is examined by benchmarking against to the technology computeraided design (TCAD) device simulations in terms of electrostatic potential profiles, band diagrams and minimum tunneling barrier width (Wt, min). As a result, the enhanced model accurately describes Wt, min in various gate voltages with different Ge mole fractions and gate oxide thicknesses. The DG heterojunction TFETs are regarded as one of the most promising successors to metal-oxide-semiconductor FETs (MOSFETs) as ultra-low-power logic devices, due to their high compatibility with complementary MOS (CMOS)-based integrated circuits (ICs) in terms of structures, materials and fabrication processes. The proposed enhanced model is expected to contribute for examining the TFETs circuit operation as well as understanding device physics, in depth, to extend Moore's Law.