In this work, we study bifacial heterojunction silicon solar cells fabricated by hot-wire CVD on both p- and n-type crystalline silicon substrates. In these devices, hydrogenated microcrystalline silicon doped layers are combined with thin intrinsic amorphous silicon buffers to form the heterojunction emitter and the low-temperature back surface field contact. The maximum temperature achieved in the whole fabrication process is 200 °C. A comprehensive electrical characterization has been done, including current density-voltage characteristics and external quantum efficiency curves with illumination from both sides. These results evidence the feasibility of efficient bifacial heterojunction silicon solar cells fully processed at low temperature.