Here we present a highly scalable reconfigurable field effect transistor concept, which is capable of dynamically switching between p-type, n-type, and ambipolar operation modes by adaptively changing the applied back-bias. The devices are processed on full-scale 300 mm wafers and reach gate lengths down to 20 nm, integrable into a 22 nm FDSOI platform with only minor process modifications. We demonstrate symmetric IV characteristics of p- and n-program with I_m/loFF ratio up to 10³ at a V_DD of 0.8 V, and propose an exploitation in hardware security. In arnbipolar mode, frequency multiplication requiring only a single transistor is experimentally demonstrated.