Impact Of Dislocations On The Thermal Conductivity Of Gallium Nitride Studied By Time-Domain Thermoreflectance

GaN thermal conductivity (.GaN) of hydride vapor phase epitaxy grown GaN (HVPE GaN), high nitride pressure grown GaN (HNP GaN), and metal-organic chemical vapor deposition grown GaN on sapphire (GaN/sapphire) and on Si(111) (GaN/Si) are measured as 204.7 (+/- 4.6), 206.6 (+/- 6.8), 191.5 (+/- 10.5), and 164.4 (+/- 3.2) W/m K, respectively, using the time-domain thermoreflectance technique. Dislocation densities (sD) of HVPE GaN, HNP GaN, GaN/sapphire, and GaN/Si are measured as 4.80 (+/- 0.42) x 10(5), 3.81 (+/- 0.08) x 106, 2.43 (+/- 0.20) x 10(8), and 1.10 (+/- 0.10) x 10(9)cm(-2), respectively, using cathodoluminescence and X-ray diffraction studies. Impurity concentrations of Si, H, C, and O are measured by secondary ion mass spectroscopy studies. The relationship between kappa(GaN) and sigma(D) is modeled through a new empirical model kappa(GaN) = 210 tanh(0.12)(1.5 x 10(8)/sigma(D)). A modified Klemens's model, where dislocation induced scattering strength is increased, is proposed to explain the experimental rate of decrease in kappa(GaN) with increasing sigma(D). Overall, this work reports how.GaN of heteroepitaxially-grown GaN can be estimated based on sigma(D), providing key design guidelines for thermal management in GaN semiconductor devices. Published under license by AIP Publishing.