Breakdown Voltage Enhancement of Vertical Diamond Schottky Barrier Diode With Annealing Method and AlO Field Plate Structure

We proposed a simple method to enhance the breakdown voltage (BV) and reduce the turn-on voltage (VON) for diamond vertical Schottky barrier diode (SBD) with Al2O3 field plate (FP) structure. The Al2O3 was deposited by atomic layer deposition at 200 °C. Ti/Pt/Au and Zr/Ni/Au metal stacks were used as ohmic and Schottky electrodes, respectively. Then, this FP terminated SBD was annealed at 400 °C to improve Al2O3 quality and lower Schottky barrier height. The ideality factor and Schottky barrier height are 1.60 and 1.42 eV, respectively. Compared with regular diamond SBD, the BV of annealed diamond SBD was enhanced from 162 V to 386 V with an increasement of 138%, and the VON was decreased from −2.30 to −1.65 V. This method is potential for the development of diamond power devices.