Transparent, conductive bulk GaN by high temperature ammonothermal growth

Jiang, Wenkan; Ehrentraut, Dirk; Cook, J. Desmond; Kamber, Derrick S.; Pakalapati, Rajeev T.; D'Evelyn, Mark P.

doi:10.1002/pssb.201451587

Cited by 14 publications

(27 citation statements)

References 31 publications

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“…[55] Bulk crystalsw ith 50 mm in diameter have also been demonstratedb yd ifferent research groups. [56][57][58][59] Selected high-quality bulk GaN crystals grown by the ammonothermal method are shown in Figure 2.…”

Section: Group 13 Nitridesmentioning

confidence: 99%

“…However,s uch materials have not been examined with regardt ol ong-term stability using supercritical ammonia and still requiref urther investigations.O ther concepts implement internal heaters, at hick ceramic inner shell,a nd an outer shell made of steel to circumvent materiall imitations of conventional reactors. [11,57] The low thermal conductivity of the ceramic retains the steel temperature below 470 K, where its high creep resistance is maintained. The reported vessel design sustains high pressures of up to 600 MPa at temperatures of 1025 K. Concepts from other high-pressure technologies like piston-cylinder or belt apparatus can be considered as well andh ave already been appliedf or hydrothermal processes.…”

Section: Autoclaves and Liner Conceptsmentioning

confidence: 99%

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Ammonothermal Synthesis of Nitrides: Recent Developments and Future Perspectives

Häusler

Schnick

2018

Chemistry A European J

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Nitrides represent an intriguing class of functional materials with a broad range of application fields. Within the past decade, the ammonothermal method became increasingly attractive for the synthesis and crystal growth of nitride materials. The ammonothermal approach proved to be eminently suitable for the growth of bulk III-nitride semiconductors like GaN, and furthermore provided access to numerous ternary and multinary nitrides and oxonitrides with promising optical and electronic properties. In this minireview, we will shed light on the latest research findings covering the synthesis of nitrides by this method. An overview of synthesis strategies for binary, ternary, and multinary nitrides and oxonitrides, as well as their properties and potential applications will be given. The recent development of autoclave technologies for syntheses at high temperatures and pressures, in situ methods for investigations of crystallization processes, and solubility measurements by ultrasonic velocity experiments is briefly reviewed as well. In conclusion, challenges and future perspectives regarding the synthesis and crystal growth of novel nitrides, as well as the advancement of autoclave techniques are discussed.

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Section: Group 13 Nitridesmentioning

confidence: 99%

Section: Autoclaves and Liner Conceptsmentioning

confidence: 99%

Ammonothermal Synthesis of Nitrides: Recent Developments and Future Perspectives

Häusler

Schnick

2018

Chemistry A European J

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“…Various research groups and companies are actively pursuing this technique and 2-inch diameter crystal boules have already been demonstrated. [24][25][26][27] The current state of the art crystals have a reproducible low TD densities of around 10 4 cm −2 [26][27][28][29] and wafers sliced from ammonothermally grown boules are sufficiently flat with radius of curvature in the order of several hundred meters. [20,30,31] Typical growth rates in the c-direction are in the range of a few hundred micrometers per day [22,26,32,33] and large arbitrary oriented substrates have been demonstrated.…”

Section: Progress Reportmentioning

confidence: 99%

“…The current state of the art crystals have reproducible low threading dislocation densities (TDD) of around 10 4 cm −2 [26][27][28][29] but dislocation densities as low as 10 3 cm −2 have been reported. [20,24] To continue monitoring and improving the structural quality, reliable, preferentially non-destructive dislocation characterization is essential.…”

Section: Dislocations In Ammonothermal Gallium Nitridementioning

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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“…The ammonothermal method circumvents this problem by dissolving GaN into a solution of supercritical ammonia. While its viability has been demonstrated 4,5,6,7 , improvements to growth rates are desired to reduce cost of the resulting GaN substrates. 8 Recent advances have shown that improved growth rates can be achieved for basic ammonothermal growth of GaN when performed in a silver capsule system.…”

Section: Introductionmentioning

confidence: 99%

Basic ammonothermal GaN growth in molybdenum capsules

Pimputkar¹,

Speck²,

Nakamura³

2016

Journal of Crystal Growth

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Single crystal, bulk gallium nitride (GaN) crystals were grown using the basic ammonothermal method in a high purity growth environment created using a non-hermetically sealed molybdenum (Mo) capsule and compared to growths performed in a similarly designed silver (Ag) capsule and capsule-free René 41 autoclave. Secondary ion mass spectrometry (SIMS) analysis revealed transition metal free (< 1x10 17 cm -3 ) GaN crystals. Anomalously low oxygen concentrations ((2-6)x10 18 cm -3 ) were measured in a {0001} seeded crystal boule grown using a Mo capsule, despite higher source material oxygen concentrations ((1-5)x10 19 cm -3 ) suggesting that molybdenum (or molybdenum nitrides) may act to getter oxygen under certain conditions. Total system pressure profiles from growth runs in a Mo capsule system were comparable to those without a capsule, with pressures peaking within 2 days and slowly decaying due to hydrogen diffusional losses. Measured Mo capsule GaN growth rates were comparable to un-optimized growth rates in capsule-free systems and appreciably slower than in Ag-capsule systems. Crystal quality replicated that of the GaN seed crystals for all capsule conditions, with high quality growth occurring on the (0001) Ga-face. Optical absorption and impurity concentration characterization suggests reduced concentrations of hydrogenated gallium vacancies (V Ga -H x ). 4

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Transparent, conductive bulk GaN by high temperature ammonothermal growth

Cited by 14 publications

References 31 publications

Ammonothermal Synthesis of Nitrides: Recent Developments and Future Perspectives

Ammonothermal Synthesis of Nitrides: Recent Developments and Future Perspectives

Defects in Single Crystalline Ammonothermal Gallium Nitride

Basic ammonothermal GaN growth in molybdenum capsules

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