AlGaN/GaN/GaN:C Back-Barrier HFETs With Breakdown Voltage of Over 1 kV and Low RON × A

E. Bahat-Treidel , F. Brunner, O. Hilt, E. Cho, J. Würfl, and G. Tränkle

Published in:

IEEE Trans. Electron Devices, vol. 57, no. 11, pp. 3050-3058 (2010).

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A systematic study of GaN-based heterostructure field-effect transistors with an insulating carbon-doped GaN back barrier for high-voltage operation is presented. The impact of variations of carbon doping concentration, GaN channel thickness, and substrates is evaluated. Tradeoff considerations in ON-state resistance versus current collapse are addressed. Suppression of the OFF-state subthreshold drain-leakage currents enables a breakdown voltage enhancement of over 1000 V with a low ON-state resistance. Devices with a 5-µm gate-drain separation on semi-insulating SiC and a 7-µm gate-drain separation on n-SiC exhibit 938 V and 0.39 mΩ • cm2 and 942 V and 0.39 mΩ • cm2, respectively. A power device figure of merit of ~2.3 × 109 V2/Ω • cm2 was calculated for these devices.

Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany

Index Terms:

AlGaN/GaN heterostructure field-effect transistor (HFET), insulating GaN (i-GaN).