The influence of the GaN substrate types and the active area scaling design on the conduction properties of vertical GaN MISFETs for laser driving applications

Joachim Würfl, Ferdinand-Braun-Institute, United Monolithic Semiconductors
Eldad Bahat Treidel, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Oliver Hilt, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Veit Hoffman, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Frank Brunner, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH)
Bernd Janke, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Nicole Bickel, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Hossein Yazdani, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Hassan Gargouri, SENTECH Instruments GmbH

In this work we present a systematic study on the conduction properties in vertical GaN trench MISFETs grown and manufactured on different free standing GaN substrates. It is shown that devices manufactured on ammonothermal substrates have superior conduction current density higher than 4 kA/cm2, specific on‑state resistance as low as 1.1 ± 0.1 mWcm2 and channel sheet resistance of 19.6 ± 0.9 Wmm. It is further shown that scaling these devices to large gate periphery is not limited by current spreading in the drift region, low channel mobility or by self‑heating. The conduction properties of devices manufactured on ammonothermal GaN substrates are found to be the most suitable for pulsed laser driving applications.

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