Thermal management of GaN HEMT devices using serpentine minichannel heat sinks

Abstract

An experimental and numerical investigation of water-cooled serpentine rectangular minichannel heat sinks (MCHS) has been performed to assess their suitability for the thermal management of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) devices. A Finite Element-based conjugate heat transfer model is developed, validated experimentally and used to determine the optimal minichannel width and number of minichannels for a case with a uniform heat flux of 100 W/cm 2. The optimisation process uses a 30 point Optimal Latin Hypercubes Design of Experiments, generated from a permutation genetic algorithm, and accurate metamodels built using a Moving Least Square approach. A Pareto front is then constructed to enable the compromises available between designs with a low pressure drop and those with low thermal resistance to be explored and an appropriate minichannel width and number of minichannels to be chosen. These parameters are then used within conjugate heat transfer models of a serpentine MCHS with silicon, silicon carbide, diamond and graphene heat spreaders placed above a GaN HEMT heating source of area 4.8 × 0.8 mm 2 , generating 1823 W/cm 2. A nanocrystalline diamond (NCD) layer with thickness of 2 µm is mounted on the top surface of the GaN HEMT to function as a heat spreader to mitigate the hot spots. The effect of volumetric flow rate and heat spreader thickness on the chip temperature has been investigated numerically and each of these has been shown to be influential. For example, at a volumetric flow rate of 0.10 l/min, the maximum chip temperature can be reduced from 124.7 o C to 96.7 o C by employing a 25 µm thick graphene heat spreader attached to the serpentine MCHS together with a NCD layer compared with a serpentine MCHS without these heat spreaders.

High In-Plane Thermal Conductivity of Aluminum Nitride Thin Films

“…Thermal dissipation from hot spots presents a bottleneck to the efficient and reliable operation of electronic devices, ranging from low-power logic devices to high-power RF high electron mobility transistors. − Different techniques, such as power management, improved packaging technology, , thermoelectric cooling, heat sink design, , and lateral heat spreaders, ,, have been implemented to circumvent this problem. However, these solutions often require departure from the most efficient electronic device geometry to allow for gains in thermal dissipation.…”

Topological structures for microchannel heat sink applications – a review

“…The serpentine flow channel has been used by most researchers for its simple structure and good heat transfer characteristics. In earlier years, Hao [15] and Al-Neama [16] successively analyzed the heat transfer and flow characteristics of serpentine MCHS (Fig. 4a).…”

Numerical simulation and microchannels parameters optimization for thermal management of GaN HEMT devices

“…The optimal solutions of thermal resistance and pump power were obtained and analyzed. Al-Neama et al (Al-Neama et al, 2018) chose the number and width of microchannels as design variables and optimization objective is the minimum of thermal resistance and pressure drop. The results based on computational fluid dynamics (CFD) shown significant impact on thermal management of GaN HEMT devices.…”