Reduction of on-resistance and current crowding in quasi-vertical GaN power diodes

• Main Authors: Hennig, Jonas (Author), Dadgar, Armin (Author), Zhang, Yuhao (Contributor), Sun, Min (Contributor), Piedra, Daniel (Contributor), Palacios, Tomas (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science (Contributor), Massachusetts Institute of Technology. Microsystems Technology Laboratories (Contributor)
• Format: Article
• Language: English
• Published: American Institute of Physics (AIP), 2018-11-15T14:59:24Z.
• Subjects: Article
• Online Access: Get fulltext

 This paper studies the key parameters affecting on-resistance and current crowding in quasi-vertical GaN power devices by experiment and simulation. The current distribution in the drift region, n⁻-GaN, was found to be mainly determined by the sheet resistance of the current spreading layer, n⁺-GaN. The actual on-resistance of the drift region significantly depends on this current distribution rather than the intrinsic resistivity of the drift layer. As a result, the total specific on-resistance of quasi-vertical diodes shows a strong correlation with the device area and sheet resistance of the current spreading layer. By reducing the sheet resistance of the current spreading layer, the specific on-resistance of quasi-vertical GaN-on-Si power diodes has been reduced from ~10 mΩ x cm² to below 1 mΩ x cm². Design space of the specific on-resistance at different breakdown voltage levels has also been revealed in optimized quasi-vertical GaN power diodes.