High power and high efficiency InP Gunn diodes which were made from layers grown by LP-MOCVD have been developed in the millimeter-wave range. The Gunn diodes, processed using the integral heat sink technique have delivered up to 100 mw cw output power with 2,5% efficiency at 94GHz, while average power levels in excess of 90 mw were obtained at 94GHz. The Gunn diodes operated at a bulk temperature less than 200??C under maximum output power operating condition. The AM noise of the 94GHz Gunn oscillator was ??140 dbc/Hz SSB at 10KHz from the carrier.