Self-Heating in GaN Transistors Designed for High-Power Operation
J. Kuzmík1, M. Ťapajna1, L. Válik1, M. Molnár2, D. Donoval2, C. Fleury3, D. Pogany3, G. Strasser3, O. Hilt4, F. Brunner4, and J. Würfl4
Published in:
IEEE Trans. Electron Devices, vol. 61, no. 10, pp. 3429-3434 (2014).
Abstract:
DC and transient self-heating effects are investigated in normally off AlGaN/GaN transistors designed for a highpower operation. Electrical and optical methods are combined with thermal simulations; 2-µs-long voltage pulses dissipating about 4.5 W/mm are applied on four different transistor structures combining GaN or AlGaN buffer on an n-type SiC substrate with or without Ar implantation. Transistors with only 5% Al mass fraction in the buffer show almost a threefold increase in the transient self-heating if compared with devices on the GaN buffer. On the other hand, 2-µs-long pulses were found not to be long enough for the Ar-implanted SiC substrate to influence the device self-heating unless AlGaN composition changes. In the dc mode, however, both the buffer composition and Ar implantation significantly influence the self-heating effect with the highest temperature rise for the transistor having the AlGaN buffer grown on the Ar-implanted SiC. We point on possible tradeoffs between the transistor high-power design and the device thermal resistance.
1 Institute of Electrical Engineering, Slovak Academy of Sciences, Bratislava 841 04, Slovakia
2 Institute of Electronics and Photonics, Slovak University of Technology, Bratislava, Slovakia
3 Institute for Solid State Electronics, Vienna University of Technology, Vienna 1040, Austria
4 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
Index Terms:
GaN, high-electron mobility transistor (HEMT), optical characterization, thermal characterization, thermal resistance.
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