Leakage Reduction of Quasi-Vertical GaN Schottky Barrier Diode With Post Oxygen Plasma Treatment

This work presents a quasi-vertical GaN Schottky barrier diode (SBD) on sapphire substrate with oxygen (O-2) plasma treatment aftermesa etching. The fabricated diodes exhibit a high ON/ OFF current ratio of 10(10) with a low OFF-state leakage current density of 10 (8) A/cm(2) at a bias voltage of -3 V and a breakdown voltage (BV) of 180 V. Transmission electronmicroscopy (TEM) images reveal that the O-2 plasma treatment can remove the photoresist residue on the surface of GaN. As a result, the barrier height of Ni/Au anode electrode on GaN is increased and the traps caused by the addition of carbon in GaN are reduced, thus leading to a lower reverse leakage current and high BV. This work provides a good process tomake GaN on foreign substrates more practical for high power electronics applications.

Automated summary

This work presents a method to fabricate quasi-vertical GaN Schottky barrier diodes on sapphire substrates with oxygen plasma treatment. The fabricated diodes exhibit high ON/OFF current ratio and low leakage current density, as well as high breakdown voltage. The oxygen plasma treatment removes photoresist residue and improves the barrier height of the anode electrode, leading to lower leakage current and higher breakdown voltage. This work provides a good process for practical applications of GaN on foreign substrates in high power electronics.