Advanced Electronic Materials 12, no. 17 (2026): e70524, DOI: https://doi.org/10.1002/aelm.70524

Low Thermal Resistance Architectures for AlGaN-Based Semiconductor Devices

Kidus Guye¹, Davide Orlandini², Seungheon Shin², Andy Allerman³, Damena Agonafer¹, Siddharth Rajan² and Samuel Graham<sup>1

1</sup>Department of Mechanical Engineering, University of Maryland, College Park, USA
²Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio, USA
³Sandia National Laboratories, Albuquerque, New Mexico, USA

For more information about this article and related research, please contact Prof. Damena Agonafer.

Abstract:

Next-generation high-power radio-frequency (RF) devices increasingly demand transistors that operate efficiently with high gainat high frequencies. High-aluminum-content ultrawide-bandgap (UWBG) AlGaN alloys have shown great potential for enablingsuch high-frequency RF technologies. However, the widespread adoption of AlGaN-based RF devices is limited by thermal-management challenges arising from the intrinsically low thermal conductivity of AlGaN, which leads to higher device thermalresistance for a given geometry compared to GaN RF devices. As a result, these next-generation devices are highly susceptible toself-heating. This study investigates the thermal behavior of UWBG AlGaN devices, focusing on the effects of AlGaN channelthickness, substrate technology, and high-k material integration on reducing device thermal resistance to enable high-poweroperation. Experimental results demonstrate a record-low thermal resistance of 3.96 mm ⋅ K/W when an AlN substrate is employedand the AlGaN channel thickness is reduced to 5 nm. These findings provide valuable insights into mitigating thermal limitationsin UWBG devices through device-level engineering and the strategic integration of high-k materials.

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