Thick homoepitaxial GaN with low carrier concentration for high blocking voltage

Freitas, Jaime A.; Mastro, Michael A.; Imhoff, Eugene A.; Tadjer, Marko J.; Eddy, Charles R.; Kub, Francis J.

doi:10.1016/j.jcrysgro.2010.04.022

Cited by 8 publications

(8 citation statements)

References 13 publications

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“…The MOCVD homoepitaxy results in dislocation densities equal to or slightly less than the growth substrate. 22,23 For the epilayers considered here, order of magnitude estimates obtained from high-resolution X-Ray diffraction (HRXRD) measurements 24 and CL were consistent with this presumption. Variation among samples was less than 10Â.…”

Section: Synthesis and Characterizationsupporting

confidence: 73%

Size dictated thermal conductivity of GaN

Beechem

McDonald

Fuller

et al. 2016

Journal of Applied Physics

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Ion-beam processing effects on the thermal conductivity of n-GaN/sapphire (0001) High spatial resolution thermal conductivity and Raman spectroscopy investigation of hydride vapor phase epitaxy grown n -GaN/sapphire (0001): Doping dependenceThe thermal conductivity of n-and p-type doped gallium nitride (GaN) epilayers having thicknesses of 3-4 lm was investigated using time domain thermoreflectance. Despite possessing carrier concentrations ranging across 3 decades (10 15 -10 18 cm -3 ), n-type layers exhibit a nearly constant thermal conductivity of 180 W/mK. The thermal conductivity of p-type epilayers, in contrast, reduces from 160 to 110 W/mK with increased doping. These trends-and their overall reduction relative to bulk-are explained leveraging established scattering models where it is shown that, while the decrease in p-type layers is partly due to the increased impurity levels evolving from its doping, size effects play a primary role in limiting the thermal conductivity of GaN layers tens of microns thick. Device layers, even of pristine quality, will therefore exhibit thermal conductivities less than the bulk value of 240 W/mK owing to their finite thickness. Published by AIP Publishing.

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Section: Synthesis and Characterizationsupporting

confidence: 73%

Size dictated thermal conductivity of GaN

Beechem

McDonald

Fuller

et al. 2016

Journal of Applied Physics

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“…It has been demonstrated that the metal organic chemical vapor deposition (MOCVD) process can deposit thick stress-free homoepitaxial film with room temperature net free electron concentration on the order of 2 Â 10 15 /cm 3 , as verified by capacitance-voltage measurements performed at 30 1C [2]. Impurity trace analysis of this 14 mm thick film indicates that low background impurity levels were achieved, which is a basic requirement for high breakdown blocking layers in fast switches.…”

Section: Introductionmentioning

confidence: 81%

Structural and optical studies of thick freestanding GaN films deposited by Hydride vapor phase epitaxy

Freitas¹,

Mastro²,

Glaser³

et al. 2012

Journal of Crystal Growth

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“…6,7) Few single-crystal GaN substrates have been fabricated until recently and, consequently, most GaN-based devices had been grown on heterogeneous substrates such as sapphire, SiC, or Si. [8][9][10][11][12] Additionally, the highpurity epitaxial layers of GaN that are needed for drift layers of vertical-type power devices are difficult to grow by conventional metal-organic chemical vapor deposition (MOCVD), because of the inevitable incorporation of carbon from metalorganic sources, 5,[13][14][15] despite the great success of MOCVD in the commercialization of optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

“…Although the above mentioned studies have shown the potential benefits of GaN-based vertical-type power devices, it remains difficult to produce high-purity layers of GaN by MOCVD due to the presence of residual carbon impurities in the range 10 15 to 10 17 cm −3 . 5,[13][14][15] The enhanced incorporation of carbon under the high-growth-rate conditions needed to produce thick drift layers 15) is another potential obstacle to the application of the MOCVD method in future mass production of power devices.…”

Section: Introductionmentioning

confidence: 99%

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

Fujikura

Konno

Yoshida

et al. 2017

Jpn. J. Appl. Phys.

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Thick (20–30 µm) layers of highly pure GaN with device-quality smooth as-grown surfaces were prepared on freestanding GaN substrates by using our advanced hydride-vapor-phase epitaxy (HVPE) system. Removal of quartz parts from the HVPE system markedly reduced concentrations of residual impurities to below the limits of detection by secondary-ion mass spectrometry. Appropriate gas-flow management in the HVPE system realized device-quality, smooth, as-grown surfaces with an excellent uniformity of thickness. The undoped GaN layer showed insulating properties. By Si doping, the electron concentration could be controlled over a wide range, down to 2 × 1014 cm−3, with a maximum mobility of 1150 cm2·V−1·s−1. The concentration of residual deep levels in lightly Si-doped layers was in the 1014 cm−3 range or less throughout the entire 2-in. wafer surface. These achievements clearly demonstrate the potential of HVPE as a tool for epitaxial growth of power-device structures.

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Thick homoepitaxial GaN with low carrier concentration for high blocking voltage

Cited by 8 publications

References 13 publications

Size dictated thermal conductivity of GaN

Size dictated thermal conductivity of GaN

Structural and optical studies of thick freestanding GaN films deposited by Hydride vapor phase epitaxy

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

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