Abstract
This study introduces an enhanced thermal management strategy for efficient heat dissipation from GaN power amplifiers with high power densities. The advantages of applying an advanced liquid-looped silicon-based micro-pin fin heat sink (MPFHS) as the mounting plate for GaN devices are illustrated using both experimental and 3D finite element model thermal simulation methods, then compared against traditional mounting materials. An IR thermography system was equipped to obtain the temperature distribution of GaN mounted on three different plates. The influence of mass flow rate on a MPFHS was also investigated in the experiments. Simulation results showed that GaN device performance could be improved by increasing the thermal conductivity of mounting plates’ materials. The dissipated power density of the GaN power amplifier increased 17.5 times when the mounting plate was changed from LTCC (Low Temperature Co-fired Ceramics) (k = 2 Wm−1 K−1) to HTCC (High-Temperature Co-fired Ceramics) (k = 180 Wm−1 K−1). Experiment results indicate that the GaN device performance was significantly improved by applying liquid-looped MPFHS, with the maximum dissipated power density reaching 7250 W/cm2. A thermal resistance model for the whole system, replacing traditional plates (PCB (Printed Circuit Board), silicon wafer and LTCC/HTCC) with an MPFHS plate, could significantly reduce θjs (thermal resistance of junction to sink) to its theoretical limitation value.
Highlights
As a third-generation semiconductor material, GaN is advantageous over silicon and GaAs materials in its wide bandgap, electron saturation migration speed, breakdown field strength and operating temperature
Experiment results indicate that the GaN device performance was significantly improved by applying liquid-looped micro-pin fin heat sink (MPFHS), with the maximum dissipated power density reaching 7250 W/cm2
2 oftemperature of a GaN power amplifier (PA) grown on SiC substrates mounted on different plates, including PCB, lateral heat spreader than an effective heat sink [8,9]
Summary
As a third-generation semiconductor material, GaN is advantageous over silicon and GaAs materials in its wide bandgap, electron saturation migration speed, breakdown field strength and operating temperature. Convective flow in a micro-pin fin heat sink (MPFHS) has been identified as a promising cooling strategy for heat dissipation in such high heat flux chips [10]. It is superior in terms of the adequate heat exchange area between a heat source and liquid, which is ascribed to the high aspect ratio of the structure [11]. Ratio of the structure [11] In this was paper, IR thermography measurements conducted results, to explore the device thermal simulation conducted to correlate with thewere experiment which was compared temperature of a GaN power amplifier (PA) grown on SiC substrates mounted on different plates, with traditional mounting materials with different thermal conductivities such as HTCC/LTCC including PCB, bare silicon wafer and a liquid-looped Si-based MPFHS.
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