Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
High Thermal Conductivity of Gallium Nitride (GaN) Crystals Grown by HVPE Process
Hiroyuki ShibataYoshio WasedaHiromichi OhtaKazumasa KiyomiKenji ShimoyamaKenji FujitoHirobumi NagaokaYuji KagamitaniRayko SimuraTsuguo Fukuda
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2007 Volume 48 Issue 10 Pages 2782-2786


A relatively large sample of gallium nitride (GaN) was grown as a single crystal using the hydride vapor phase epitaxy (HVPE) process. The thermal diffusivity of the single crystal has been measured using a vertical-type laser flash method. The thermal expansion was measured using a dilatometer in order to estimate the thermal diffusivity with sufficient reliability. The effect of sample thickness and temperature on thermal diffusivity was evaluated. The specific heat capacity of GaN was also measured by using a differential scanning calorimeter. The thermal properties of single-crystal GaN have been compared with the measured thermal properties of single-crystal silicon carbide (SiC). The thermal conductivity of single-crystal GaN at room temperature is found to be 253±8.8% W/mK, which is approximately 60% of the value obtained for SiC. The excellent thermal property that is obtained in this study clearly indicates that GaN crystals are one of the promising materials for use in high-power-switching devices.

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© 2007 The Japan Institute of Metals and Materials
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