Al ₀ .3 Ga 0.7 N PN diode with breakdown voltage >1600 V

Demonstration of Al 0.3 Ga 0.7 N PN diodes grown with breakdown voltages in excess of 1600 V is reported. The total epilayer thickness is 9.1 μm and was grown by metal‐organic vapour‐phase epitaxy on 1.3‐mm‐thick sapphire in order to achieve crack‐free structures. A junction termination edge structure was employed to control the lateral electric fields. A current density of 3.5 kA/cm 2 was achieved under DC forward bias and a reverse leakage current <3 nA was measured for voltages <1200 V. The differential on‐resistance of 16 mΩ cm 2 is limited by the lateral conductivity of the n‐type contact layer required by the front‐surface contact geometry of the device. An effective critical electric field of 5.9 MV/cm was determined from the epilayer properties and the reverse current–voltage characteristics. To our knowledge, this is the first aluminium gallium nitride (AlGaN)‐based PN diode exhibiting a breakdown voltage in excess of 1 kV. It is noted that a Baliga figure of merit ( V br 2 /R spec , on ) of 150 MW/cm 2 found is the highest reported for an AlGaN PN diode and illustrates the potential of larger‐bandgap AlGaN alloys for high‐voltage devices.