Diamond for enhanced GaN device performance

Ejeckam, F.; Francis, Daniel; Faili, Firooz; Dodson, Joe; Twitchen, Daniel J.; Bolliger, Bruce; Babic, D.I.

doi:10.1109/itherm.2014.6892417

Cited by 9 publications

(2 citation statements)

References 7 publications

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“…To dissipate the high concentrated heat flux, the effective heat spreading capability is quite significant as well. Chemical Vapour Deposition (CVD) diamond heat spreaders are particularly suited for such applications [11][12][13][14][15].…”

Section: Background Informationmentioning

confidence: 99%

Optimizing Diamond Heat Spreaders for Thermal Management of Hotspots for GaN Devices

Obeloer

Bolliger

Han

et al. 2015

International Symposium on Microelectronics

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As devices become smaller while still requiring high reliability in the presence of extreme power densities, new thermal management solutions are needed. Nowhere is this more evident than with the use of Gallium Nitride (GaN) transistors, where engineers struggle with the thermal barriers limiting the ability to achieve the intrinsic performance potential of GaN semiconductor devices. Emerging as a common solution to this GaN thermal management challenge are metallized diamond heat spreaders. In this paper, a diamond heat spreader has been applied with a hybrid Si micro-cooler for to cool GaN devices. Several different grades and thicknesses of microwave CVD diamond heat spreaders, as well as various bonding layers, are characterized for their thermal effects. The heat spreader is bonded through a TCB (thermal compression bonding) process to a Si thermal test chip designed to mimic the hotspots of 8 GaN units. The heat dissipation capabilities were compared through experimental tests and fluid-solid coupling simulations, both showing consistent results. In one configuration, using a diamond heat spreader 400μm thick with a thermal conductivity > 2000W/mK, to dissipate 70W heating power, the maximum chip temperature can be reduced by 40.4%, for test chips 100μm thick. And 10kW/cm2 hotspot heat flux can be dissipated while maintaining the maximum hotspot temperature under 160ºC. The concentrated heat flux has been effectively reduced by the diamond heat spreader, and much better cooling capability of the Si micro-cooler has been achieved for high power GaN devices.

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Section: Background Informationmentioning

confidence: 99%

Optimizing Diamond Heat Spreaders for Thermal Management of Hotspots for GaN Devices

Obeloer

Bolliger

Han

et al. 2015

International Symposium on Microelectronics

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“…The reverse approach, the growth of diamond on AlGaN/GaN was demonstrated both on the top [10] or the bottom [11] of the GaN layer and already competes with the GaN-on-SiC technology [12,13]. The most developed GaN-on-diamond process grows PCD on the nitrogen-face GaN buffer layer with a thin interfacial stabilization layer [14]. Extensive reliability testing [15], scaling to 4-inch wafer size [11], and RF-performance of 7.9 W mm −1 ( P out ) atpower-added-efficiency (PAE) of 46% [16] (10 GHz, 40 V bias) demonstrated already its efficiency for next-generation high-power semiconductor devices.…”

Section: Introductionmentioning

confidence: 99%

Transfer of AlGaN/GaN RF-devices onto diamond substrates via van der Waals bonding

Gerrer

Cimalla

Waltereit

et al. 2018

Int. J. Microw. Wireless Technol.

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We present a novel bonding process for gallium nitride-based electronic devices on diamond heat spreaders. In the proposed technology, GaN devices are transferred from silicon (Si) onto single (SCD) and polycrystalline diamond (PCD) substrates by van der Waals bonding. Load-pull measurements on Si and SCD heat spreaders at 3 GHz and 50 V drain bias show comparable power-added-efficiency and output power (Pout) levels. A thermal analysis of the hybrids was performed by comparison of 2 × 1mm2AlGaN/GaN Schottky diodes on Si, PCD, and SCD, which exhibit a homogeneous field in the channel in contrast to gated transistors. Significantly different currents are observed due to the temperature dependent mobility in the 2DEG channel. These measurements are supported by a 3D thermal finite element analysis, which suggests a large impact of our transfer technique on the thermal resistance of these devices. In summary, we show a promising new GaN-on-diamond technology for future high-power, microwave GaN device applications.

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