Efficient fundamental frequency oscillation from millimetre-wave indium phosphide n+-n-n+ transferred electron oscillators

The letter describes the development of CW indium phosphide, transferred-electron oscillators (TEOs) with emphasis being place on the achievement of efficient operation in the millimetre-wave frequency range. Reasons are given for the choice of the n+-n-n+ epitaxial structure used, together with relevant material growth and characterisation details. A brief outline of the device fabrication technology is given before discussing oscillator performances. Results are presented for operating frequencies from 30 to 110 GHz which show that the three-layer indium phosphide device is capable of much higher conversion efficiencies than the equivalent gallium arsenide structure at frequencies above 40 GHz. From these figures it is concluded that indium phosphide will supplant gallium arsenide as a mm-wave TEO material.