Slanted Tri-Gates for High-Voltage GaN Power Devices

• Published in: IEEE electron device letters 2017-09, Vol.38 (9), p.1305-1308
• Main Authors: Ma, Jun, Matioli, Elison
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitride; breakdown; Electric breakdown; Electric fields; field plate; Gallium nitride; GaN; HEMT; Logic gates; Nanowires; slanted tri-gate; tri-gate; Wide band gap semiconductors
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2017.2731799

In this letter, we introduce and demonstrate the concept of slanted tri-gates to enhance the breakdown voltage (V BR ) in lateral GaN power devices. Conventionally, field plates (FPs) are used to enhance the VBR by distributing more homogeneously the electric field near the gate electrode, which is mainly determined by their pinch-off voltage (V p ). These FPs however rely on a vertical approach, in which V p is usually designed via the thickness of the FP oxide. On the other hand, the slanted tri-gate relies on a lateral design to tailor its V p , by simply changing the width (w) of their nanowires lithographically. Here, we demonstrate this concept for AlGaN/GaN-on-silicon MOSHEMTs resulting in an increase of ~500 V in V BR compared with the counterpart planar devices. These devices presented a high V BR of 1350 V with a small gate-to-drain separation (L GD ) of 10 μm, along with a record high-power figure-of-merit of 1.2 GW/cm 2 among GaN-on-silicon lateral transistors.