High-Pressure, High-Temperature Solution Growth and Ammonothermal Synthesis of Gallium Nitride Crystals

Ehrentraut, Dirk; Boćkowski, Michał

doi:10.1016/b978-0-444-63303-3.00015-8

Cited by 15 publications

(35 citation statements)

References 105 publications

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“…[46] Given the high activity of nitrogen in this environment, ammonothermal synthesis of nitrides, of which GaN is the best known and researched example, is readily achieved. [47] The underlying process revolves around the dissolution of gallium (Ga) from a Ga containing source (typically polycrystalline GaN) into the supercritical ammonia solution, transport of the Ga species to a high quality GaN seed crystal, which is situated at a different temperature, and crystallization from the solution onto the growing GaN crystal.…”

Section: Ammonothermal Growth Of 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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Section: Ammonothermal Growth Of Gallium Nitridementioning

confidence: 99%

Defects in Single Crystalline Ammonothermal Gallium Nitride

Suihkonen

Pimputkar

Sintonen

et al. 2017

Adv Elect Materials

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“…The use of an internal heating allows the application of higher temperatures and higher pressures compared to autoclaves made of nickel based superalloys, additionally the use of conventional steel is less expensive in production and processing [39]. Nickel based superalloys, for example, Inconel 750 [6], Vacumelt ATS 340 [3], Inconel 718 [59] and Rene 41 [36] are used for the construction of high pressure autoclaves with external heating. Those superalloys almost resist corrosion in ammonobasic milieu up to temperatures of ∼873 K at ≥3000 MPa (Inconel 750) and can stand even ≤1123 K at ≤150 MPa (Rene 41) [62].…”

Section: Reaction Vesselsmentioning

confidence: 99%

“…High quality of the substrate is very important, since it allows the production of more devices per substrate and devices made of low-defect-density GaN or AlN promise longer working periods at higher power without breakdown [43]. Solvothermal methods in general are known for their reliable and scalable process, which permits the efficient growth of a great number of crystals within one synthesis, e.g., 1400 quartz crystals, 1700 g each [36,44].…”

mentioning

confidence: 99%

“…Wafers are cut from the formed bulk material and subsequently polished. They can be used in devices or as a substrate for further syntheses [36]. Metal organic vapor phase epitaxy allows the growth of thin epitaxial layers used for devices.…”

mentioning

confidence: 99%

“…Metalorganic precursors (e.g., triethyl or trimethyl-gallium) react with NH 3 forming GaN on a substrate. Growth rates vary from 1-2 µm/h for thin layers and up to 50 µm/h for bulk growth [36].…”

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Chemistry of Ammonothermal Synthesis

2014

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Ammonothermal synthesis is a method for synthesis and crystal growth suitable for a large range of chemically different materials, such as nitrides (e.g., GaN, AlN), amides (e.g., LiNH 2 , Zn(NH 2 ) 2 ), imides (e.g., Th(NH) 2 ), ammoniates (e.g., Ga(NH 3 ) 3 F 3 , [Al(NH 3 ) 6 ]I 3 · NH 3 ) and non-nitrogen compounds like hydroxides, hydrogen sulfides and polychalcogenides (e.g., NaOH, LiHS, CaS, Cs 2 Te 5 ). In particular, large scale production of high quality crystals is possible, due to comparatively simple scalability of the experimental set-up. The ammonothermal method is defined as employing a heterogeneous reaction in ammonia as one homogenous fluid close to or in supercritical state. Three types of milieus may be applied during ammonothermal synthesis: ammonobasic, ammononeutral or ammonoacidic, evoked by the used starting materials and mineralizers, strongly influencing the obtained products. There is little known about the dissolution and materials transport processes or the deposition mechanisms during ammonothermal crystal growth. However, the initial results indicate the possible nature of different intermediate species present in the respective milieus. A Alkali or alkaline-earth metal, A(1) = alkali metal, A(2) = alkaline-earth metal B Further metal, might be main group metal, transition or rare-earth metal M Transition metal, excluding Sc, Y, La R Rare-earth metal, Sc, Y, La-Lu X Halide E Other main group element

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