High breakdown voltage achieved on AlGaN/GaN HEMTs with integrated slant field plates

A self-aligned slant-field-plate technology is presented as an improvement over the discrete multiple field plates for high breakdown voltage AlGaN/GaN HEMTs. Devices were tested in Fluorinert to eliminate the breakdown of air, which was identified to limit the breakdown voltage in AlGaN/GaN HEMTs. A single integrated field plate, which is self-aligned with the gate, is shown to support more than a kilovolt breakdown voltage (V-br up to 1900 V was measured with Fluorinert). Devices made with this technology show a good large signal-frequency behavior. Various issues regarding breakdown measurements and interpretation of measurement results are presented.