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The use of Aluminum Gallium Nitride (AlGaN) as a power switching device material has been a promising topic of research in recent years. Along with Silicon Carbide (SiC) and Gallium Nitride (GaN), AlGaN is categorized as a Wideband Gap (WBG) material with intrinsic properties best suited for high power switching applications. This paper simulates and compares the thermal and electrical performance of AlGaN and Silicon (Si) MOSFETs, modeled in COMSOL Multiphysics. Comparisons between similar AlGaN/GaN and Si power modules are made in terms of heatsink requirements. The temperatures for the same operating voltage are found to be significantly lower for the AlGaN MOSFETs structures, compared to Si. The heatsink size for the AlGaN/GaN is found to be smaller compared to Si for the power modules.

Wide Bandgap (WBG) semiconductor devices are becoming the simpler and cheaper option as compared to the limited capabilities of Si devices because of their better blocking voltages, switching frequencies, thermal conductivities and operating temperatures. WBG semiconductors like Gallium Nitride (GaN) have better materials properties specifically suited for high power and high frequency electronics and they are slowly being favored for such applications. GaN High Electron Mobility Transistors (HEMTs) have demonstrated superior performance characteristics as compared to Si Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) in terms of switching characteristics and switching losses. One particular GaN HEMT module investigated by the authors has been calculated to have less than five times the switching losses as compared to a similar Si MOSFET module under the same operating conditions. The use of the GaN module instead of Si module in an inverter application has also shown reduction of power losses and heatsink volume by 60% and 30% respectively for the GaN module. This paper investigates the effect of different heatsink materials (Aluminum, Copper, AlSiC and E-Material) on the overall temperature profile of the GaN module. The heatsink structure used for the simulations were obtained from commercially available straight-fin heatsink designs. Comparisons among these heatsink materials were done for the same operating and ambient conditions by simulating the combined HEMT-Heatsink structure in the Finite Element Analysis (FEA) software COMSOL Multiphysics. The simulation results indicated Copper to be the best heatsink material among the four materials tested.

This paper investigates the thermal performance of different wide bandgap (WBG) materials for their applicability as semiconductor material in power electronic devices. In particular, Silicon Carbide (SiC) and Gallium Nitride (GaN) are modeled for this purpose. These WBG materials have been known to show superior intrinsic material properties as compared to Silicon (Si), such as higher carrier mobility, lower electrical and thermal resistance. These unique properties have allowed for them to be used in power devices that can operate at higher voltages, temperatures and switching speeds with higher efficiencies. Digital prototyping of power devices have facilitated inexpensive and flexible methods for faster device development. The commercial simulation software COMSOL Multiphysics was used to simulate a 2-D model of MOSFETs of these WBG materials to observe their thermal performance under different voltage and current operating conditions. COMSOL is a simulation software that can be used to simulate temperature changes due to Joule heating in the case of power MOSFETs. COMSOL uses Finite Element/Volume Analysis methods to solve for variables in complex geometries where multiple material properties and physics are involved. The Semiconductor and Heat Transfer with Solids modules of COMSOL were used to study the thermal performance of the MOSFETs in steady state conditions. The results of the simulations for each of the two WBG materials were compared with that of Silicon to determine relative stability and merit of each material.