Thermal Performance of AlGaN/GaN HEMTs on SiC Substrates

Vasilevska, M. , Al-Khalidi, A. and Wasige, E. (2018) Thermal Performance of AlGaN/GaN HEMTs on SiC Substrates. UK Nitrides Consortium Summer Meeting, Sheffield, UK, 12-13 Jul 2017.

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Self-heating is one of the major issues of the existing gallium nitride (GaN) high electron mobility transistor (HEMT) technology. A significant factor that restricts heat flow from the device channel into the substrate arises from the low thermal conductivity of the aluminum nitride (AlN) nucleation layer that is usually grown between the GaN channel and the foreign substrate to reduce the lattice mismatch between the two materials. The nucleation layer results in a thermal boundary resistance (TBR) which reduces the thermal efficiency of the device by limiting the heat dissipation from the device into the substrate. In this work, a comparison between devices grown on silicon carbide (SiC) wafers from two different manufacturers (one manufacturer claiming very low TBR values) will be shown. The influence of the channel self-heating will be demonstrated using devices with variable gate widths of 10, 100 and 200 microns. On one wafer, one finger devices without optimized ohmic contacts, that have gate widths of 10 μm exhibit a high current density of 500 mA/mm at 0V gate voltage compared to 360 mA/mm of devices with gate widths of 200 μm, while a two-finger 200 μm wide device has a current density of only 330 mA/mm, indicating the impact of thermal crosstalk between fingers.

Item Type:Conference or Workshop Item
Glasgow Author(s) Enlighten ID:Wasige, Professor Edward and Elksne, Mrs Maira and Al-Khalidi, Dr Abdullah
Authors: Vasilevska, M., Al-Khalidi, A., and Wasige, E.
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering

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