Interdependence of Electronic and Thermal Transport in Al<sub>x</sub>Ga<sub>1–x</sub>N Channel HEMTs
Bikramjit Chatterjee, James Spencer Lundh, Yiwen Song, Daniel Shoemaker, Albert G. Baca, Robert Kaplar, Thomas E. Beechem, Christopher B. Saltonstall, Andrew A. Allerman, Andrew Armstrong, Brianna Klein, Anushka Bansal, Hamid Reza Seyf, Disha Talreja, Alexej Pogrebnyakov, Eric R. Heller, Venkatraman Gopalan, Asegun Henry, Joan M. Redwing, Brian M. Foley, Sukwon Choi
Abstract
Aluminum gallium nitride (AlGaN) high electron mobility transistors (HEMTs) are candidates for next-generation power conversion and radio frequency (RF) applications. Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> N channel HEMT devices (x = 0.3, x = 0.7) were investigated using multiple in-situ thermal characterization methods and electro-thermal simulation. The thermal conductivity, contact resistivity, and channel mobility were characterized as a function of temperature to understand and compare the heat generation profile and electro-thermal transport within these devices. In contrast to GaN-based HEMTs, the electrical output characteristics of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.70</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.30</sub> N channel HEMTs exhibit remarkably lower sensitivity to the ambient temperature rise. Also, during 10kHz pulsed operation, the difference in peak temperature between the AlGaN channel HEMTs and GaN HEMTs reduced significantly.