Overlapping source field plate process module for high-voltage GaN HFETs with low off state leakage currents
H. Halhoul, R.-S. Unger, F. Brunner and O. Hilt
Published in:
Int. Conf. on Compound Semiconductor Manufacturing Technology (CS ManTech 2024), Tucson, USA, May 20-23, p. 2.1.4.2024 (2024).
Abstract:
GaN-based high-voltage HFETs have been fabricated using single source-connected field plates. The device breakdown voltage was as high as 2370 V for 15.5 μm gate drain separation. A breakdown-voltage scaling as function of the gate-drain separation of 150 V/μm was achieved benefiting from the use of AlN as a buffer layer. The off-state leakage current associated with strain induced by the 2nd SiNx passivation layer decreased by around one order of magnitude after releasing this strain by opening the SiNx on top of the gate metal stripes. These openings were filled with BCB before the field plate metallization. This offers a high power figures of merit of 1.309 GW/cm2 without a penalty on the off-state leakage current.
Ferdinand-Braun-Institut gGmbH, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
Keywords:
GaN, AlN, high field effect transistors, HFETs, Breakdown voltage, source field plates, SiNx, power transistors
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