A high frequency transferred electron device having electron ballistic injection and extraction for very high efficiency is disclosed. The device comprises a semiconductor body having at least two electrodes with a thin barrier layer being formed at one electrode for launching ballistic electrons at a controlled kinetic energy into the body. The body includes a drift region having a low, controlled density of electrons and impurities. A second heavily doped (N+) collector semiconductor layer at the second electrode insures that there is no barrier at the second electrode interface, thereby allowing energetic electrons to be removed from the drift region and allowing entry of new ballistic electrons to improve the efficiency and frequency response of the device.