Bulk ammonothermal GaN

Dwiliński, R.; Doradziński, R.; Garczyński, J.; Sierzputowski, L.; Puchalski, A.; Kanbara, Y.; Yagi, Kazuichi; Minakuchi, Hiroyoshi; Hayashi, Hiroaki

doi:10.1016/j.jcrysgro.2009.01.052

Cited by 177 publications

(146 citation statements)

References 26 publications

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“…[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. [26,[34][35][36] Ammonothermal GaN substrates have been used in homoepitaxy [35,37,38] and as substrates for InGaN LDs.…”

Section: Progress Reportmentioning

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: Progress Reportmentioning

confidence: 99%

Defects in Single Crystalline Ammonothermal Gallium Nitride

Suihkonen

Pimputkar

Sintonen

et al. 2017

Adv Elect Materials

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“…Ammonothermal bulk GaN crystals can be grown with an intended conductivity level by controlling the unintentional oxygen content during the growth process, leading to an electron concentration up to~10 20 cm −3 (n-type) and an intentional Mg concentration up to~10 19 cm −3 (p-type) [7]. The ammonothermal method can also obtain semi-insulating (SI) GaN crystals which are crucial for power electronics [8] via appropriate compensation of oxygen donors by Mg acceptors.…”

Section: Introductionmentioning

confidence: 99%

Transparency of Semi-Insulating, n-Type, and p-Type Ammonothermal GaN Substrates in the Near-Infrared, Mid-Infrared, and THz Spectral Range

et al. 2017

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GaN substrates grown by the ammonothermal method are analyzed by Fast Fourier Transformation Spectroscopy in order to study the impact of doping (both n-and p-type) on their transparency in the near-infrared, mid-infrared, and terahertz spectral range. It is shown that the introduction of dopants causes a decrease in transparency of GaN substrates in a broad spectral range which is attributed to absorption on free carriers (n-type samples) or dopant ionization (p-type samples). In the mid-infrared the transparency cut-off, which for a semi-insulating GaN is at~7 µm due to an absorption on a second harmonic of optical phonons, shifts towards shorter wavelengths due to an absorption on free carriers up to~1 µm at n~10 20 cm −3 doping level. Moreover, a semi-insulating GaN crystal shows good transparency in the 1-10 THz range, while for n-and p-type crystal, the transparency in this spectral region is significantly quenched below 1%. In addition, it is shown that in the visible spectral region n-type GaN substrates with a carrier concentration below 10 18 cm −3 are highly transparent with the absorption coefficient below 3 cm −1 at 450 nm, a satisfactory condition for light emitting diodes and laser diodes operating in this spectral range.

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“…However, these methods employed polycrystalline GaN as seeds in order to grow the material. Other specific growth parameters related to this method are, high ammonia (NH 3 ) pressure in the system (between 150-500 MPa), temperature in the range of 500-600 °C and a long growth time that could take several hours [2][3][4][5][6][7][8] . Optimization of the system in order to improve the growth rate and purity are in progress [9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Gallium Nitride and Related Oxides Via Ammonobasic Reactive Sublimation (ARS)

et al. 2017

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Ammonobasic reactive sublimation (ARS) is proposed as a novel method to synthesize GaN and related oxides. Results indicate that GaN growth occurs by a nitriding process of Ga and related oxides, establishing a direct dependence on NH 4 OH amount added as a primary chemical reactive. The samples were grown on p-type Si (111) substrates inside a tube furnace, employing GaN powder and NH 4 OH. The characterizations of the samples were carried out by XRD, SEM, EDS and PL techniques, revealing the influence of NH 4 OH on the improvement of GaN synthesis and the enhancement of its optical and structural properties.

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Bulk ammonothermal GaN

Cited by 177 publications

References 26 publications

Defects in Single Crystalline Ammonothermal Gallium Nitride

Defects in Single Crystalline Ammonothermal Gallium Nitride

Transparency of Semi-Insulating, n-Type, and p-Type Ammonothermal GaN Substrates in the Near-Infrared, Mid-Infrared, and THz Spectral Range

Synthesis of Gallium Nitride and Related Oxides Via Ammonobasic Reactive Sublimation (ARS)

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