Impacts of diamond heat spreader on the thermo-mechanical characteristics of high-power AlGaN/GaN HEMTs

• The impacts of diamond heat spreader on the static and transient thermo-mechanical responses of AlGaN/GaN HEMT are studied.
• The TBR and temperature-dependent properties of physical parameters are considered and treated appropriately.
• The trade-off between the effects of diamond heat spreader on both temperature and thermal stress is necessary.

The impacts of diamond heat spreader on the static and transient thermo-mechanical responses of AlGaN/GaN HEMT are studied in this paper, with an efficient hybrid time-domain finite-element method (TD-FEM) algorithm adopted for their thermo-mechanical analysis. The algorithm accuracy is verified in comparison with either experimental or commercial software result. In particular, the thermal boundary resistance (TBR) and temperature-dependent properties of thermal conductivities and Young's modulus are considered and treated appropriately in our numerical analysis. It is shown that, there is one trade-off as we take account of the effects of diamond heat spreader on both temperature and thermal stress of the structure, which is necessary for the design, optimization, and applications of most high-power AlGaN/GaN HEMTs.