The invention relates to an
IMPATT diode with double heterojunctions and a composite
passivation layer. The
IMPATT diode with the double heterojunctions and the composite
passivation layer includes asubstrate layer, an epitaxial layer, an
ohmic contact layer, a first drift region, a second drift region, an avalanche region,
ohmic contact electrodes, a first
passivation layer, a second passivationlayer, and a Schottky
contact electrode; the epitaxial layer is located on the upper layer of the substrate layer; the
ohmic contact layer is located on the upper layer in the middle of the epitaxiallayer; the first drift region is located on the upper layer in the middle of the ohmic
contact layer; the second drift region is located on the upper layer of the first drift region; the avalanche region is located on the upper layer of the second drift region; the ohmic contact electrodes are located on both sides of the ohmic
contact layer and the upper layer of both sides of the ohmic contactlayer; the first passivation layer is located on the upper layer of the ohmic
contact layer and the upper layer of the ohmic contact electrodes, and is located on both sides of the first drift region,on both sides of the second drift region, and on both sides of the avalanche region; the second passivation layer is located on the upper layer of the first passivation layer; and the Schottky
contact electrode is located on the upper layer of the avalanche region and the upper layer of the second passivation layer. The
IMPATT diode with the double heterojunctions and the composite passivation layer provided by the invention increases the carrier
ionization rate in the avalanche region, and the
avalanche effect is limited to avalanche region; therefore, the avalanche region width is reduced,and the
power output capability is improved.