Plane Dependent Growth of GaN in Supercritical Basic Ammonia

Saitô, Makoto; Kamber, Derrick S.; Baker, Troy J.; Fujito, Kenji; DenBaars, Steven P.; Speck, James S.; Nakamura, Shuji

doi:10.1143/apex.1.121103

Cited by 24 publications

(20 citation statements)

References 22 publications

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“…[40,73,74] In basic ammonothermal growth the fastest growth rates are generally observed in the N polar -c-direction and in the a-direction, while the slow growth rate in the m-direction leads to the formation of m-plane facets bounding the grown crystal. [40,74,75] The presence of several growth facets during the process leads to the formation of distinct growth regions in the ammonothermally grown crystal. [40,74] It is well known that the incorporation efficiency of impurity species from the growth atmosphere to the growing crystal is strongly dependent on the growth rate and direction.…”

Section: Growth Regions In Ammonothermal Growthmentioning

confidence: 99%

Defects in Single Crystalline Ammonothermal Gallium Nitride

Suihkonen

Pimputkar

Sintonen

et al. 2017

Adv Elect Materials

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Native bulk gallium nitride (GaN) has emerged as an alternative for sapphire and silicon as a substrate material for III‐N devices. While quasi‐bulk GaN substrates are currently commercially available, single crystal GaN substrates are considered essential for future high performance light emitters and power devices. The ammonothermal method is currently considered one of the most feasible methods to grow large truly bulk crystals of GaN at low cost and high structural quality. High crystalline quality GaN substrates sliced from ammonothermally grown crystals have been demonstrated and utilized in homoepitaxy for III‐N devices. However, despite the high crystalline quality the properties of as‐grown ammonothermal GaN crystals and substrates are affected by the presence of impurities and other defects that hinder their use for device applications. Here, the main developments of ammonothermal growth of GaN and the effects of impurities, native point defects, and dislocations on the material properties are summarized. Additionally, measurement techniques that enable the evaluation of point defect concentration and low dislocation density distribution over a large area on bulk GaN substrates are reviewed.

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Section: Growth Regions In Ammonothermal Growthmentioning

confidence: 99%

Defects in Single Crystalline Ammonothermal Gallium Nitride

Suihkonen

Pimputkar

Sintonen

et al. 2017

Adv Elect Materials

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“…a majority of them are either positively charged Ga or negatively charged N in the last layer of the crystal. A recent paper by Saito et al [23] has investigated the effect of growth rate obtained from different crystallographic orientations. The highest growth rate (combining front and back face of the seed crystal) of 87 mm per day was achieved by using a (1 1 2 2) seed crystal.…”

Section: Consideration Of Solubility Chemistry and Growth Ratementioning

confidence: 99%

“…An alternative that was discussed during the 6th International Workshop on Bulk Nitride Semiconductors, held on August [23][24][25][26][27][28]2009 in Poland [4], is to fully profit from the structural perfection of GaN grown under basic ammonothermal conditions so as to use them as seed crystal for a subsequent HVPE GaN growth. The latter has been shown to yield very pure material [1].…”

Section: Introductionmentioning

confidence: 99%

Ammonothermal crystal growth of gallium nitride – A brief discussion of critical issues

Ehrentraut

Fukuda

2010

Journal of Crystal Growth

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“…The crystalline quality of this material is believed to be fully adequate for GaN-on-GaN power devices. However, unfortunately, the growth rates in Ammono's process and in similar processes being investigated by other groups [23], [27], [28] are small, generally about 1-4 m/h, despite more than a decade of development. The very low growth rates impact both the cost (currently much higher than HVPE) and the rate at which substrate size can be increased.…”

Section: Introductionmentioning

confidence: 89%

Ammonothermal Bulk GaN Substrates for Power Electronics

et al. 2013

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Soraa has developed a novel ammonothermal approach for growth of high quality, true bulk GaN crystals at a greatly reduced cost, known as SCoRA (Scalable Compact Rapid Ammonothermal). SCoRA GaN growth has been performed on seed crystals with diameters between 5 mm and 2" to thicknesses of 0.5-4 mm. The highest growth rates are greater than 40 m/h and rates in the 10-30 m/h range are routinely observed. Two-inch diameter, crackfree, free-standing, n-type bulk GaN crystals have been grown. The crystals have been characterized by a range of techniques, including x-ray diffraction rocking-curve (XRC) analysis, optical microscopy, cathodoluminescence (CL), optical spectroscopy, and capacitance-voltage measurements. The crystallinity of the grown crystals is very good, with FWHM values of 15-80 arc-sec and average dislocation densities below 510 5 cm -2 . IntroductionAlthough most attention in GaN-based power devices has focused on lateral, GaN-onSi or GaN-on-SiC devices, vertical, GaN-on-GaN power device technology is widely believed to be extremely promising. Recently, Disney et al. demonstrated vertical GaNon-GaN diodes with near-theoretical specific on-resistance as a function of breakdown voltage, substantially better than the best SiC-on-SiC or heteroepitaxial lateral GaN devices [1]. In addition, early-generation vertical GaN switches have been reported by a number of groups [2], [3], [4], [5], [6], [7], [8].It is clear that one of the largest obstacles to further development of GaN-on-GaN power electronics is the substrate. Virtually all commercial bulk GaN substrates today are fabricated by hydride vapor phase epitaxy (HVPE) after nucleation on foreign substrates and have wafer-averaged dislocation densities in the range of 310 6 cm -2 -110 7 cm -2 . These substrates became the standard for GaN-based laser diode (BluRay TM ) manufacturing in about 2005 [9] and are currently being used by Soraa for GaNon-GaN TM high-performance LED manufacturing [10]. While HVPE GaN substrates represent a considerable improvement over heteroepitaxial GaN, they have a number of limitations that limit their usefulness for power switches, including diameter, cost, and undesirably-high dislocation density. Threading dislocations act as vertical currentleakage paths in GaN device structures [11], accelerate degradation of AlGaN/GaN high electron mobility transistors (HEMTs) [12], [13], and have a well-documented negative impact on laser diode lifetime [14]. Consequently, dislocation densities below 10 4 cm -2 , as are available in GaAs and should be available in true bulk GaN, are often regarded as being necessary for vertical GaN-on-GaN power devices. 10.1149/05804.0287ecst ©The Electrochemical Society ECS Transactions, 58 (4) 287-294 (2013) 287 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 137.99.31.134 Downloaded on 2015-06-22 to IP The ammonothermal method has attracted considerable attention as a potential bulk GaN manufacturing method [15], ...

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Plane Dependent Growth of GaN in Supercritical Basic Ammonia

Cited by 24 publications

References 22 publications

Defects in Single Crystalline Ammonothermal Gallium Nitride

Defects in Single Crystalline Ammonothermal Gallium Nitride

Ammonothermal crystal growth of gallium nitride – A brief discussion of critical issues

Ammonothermal Bulk GaN Substrates for Power Electronics

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