Dislocation bending and tensile stress generation in GaN and AlGaN films

Raghavan, Srinivasan; Manning, Ian; Weng, Xiaojun; Redwing, Joan M.

doi:10.1016/j.jcrysgro.2012.08.020

Cited by 36 publications

(21 citation statements)

References 31 publications

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“…Similar behavior has been observed in compressively strained AlGaN layers. [122,123] The inclination angles are the greatest at interfaces with the largest impurity concentration changes and therefore with the largest strain gradients, in agreement with this theory. An important issue is whether new dislocations are generated at the interfaces due to the strain induced by the impurities.…”

Section: Dislocation Propagationsupporting

confidence: 85%

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: Dislocation Propagationsupporting

confidence: 85%

Defects in Single Crystalline Ammonothermal Gallium Nitride

Suihkonen

Pimputkar

Sintonen

et al. 2017

Adv Elect Materials

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“…The subsequent transition to a tensile stress due to a combination of initial island coalescence. As the results of this study will show and as has been reported in the literature [25,26]. The dislocation bending seems to be dominant reason for releasing tensile stress and hence the transition in the GaN films.…”

Section: Resultssupporting

confidence: 85%

The influence of reactor height adjustment on properties in GaN films grown on 6H-SiC by metal organic chemical vapor deposition

Tao

Liang

Xia

et al. 2014

J Mater Sci: Mater Electron

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The influence of reactor height adjustment on properties in GaN films grown on 6H-SiC by metal organic chemical vapor deposition (MOCVD) was investigated. The property of GaN epilayer was investigated by atomic force microscopy, X-ray diffraction, low-temperature (10 K) photoluminescence and the Raman scattering. It is found that, as the spacing between showerhead and susceptor decreased, the growth rate increased and the tensile stress decreased. This result may be useful to control the stress in GaN thin films grown on silicon carbide substrate by MOCVD.

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“…To simulate relaxation of the compressive mismatch stress, intrinsic for GaN grown on AlGaN nucleation/buffer layers, we use a kinetic model, whose basic postulates are discussed in Refs. . Within the model, relaxation of the compressive stress occurs due to inclination of a ‐type TDs, which agrees with experimental findings .…”

Section: Modeling Approachsupporting

confidence: 87%

“…. Within the model, relaxation of the compressive stress occurs due to inclination of a ‐type TDs, which agrees with experimental findings . The inclination is considered as outdiffusion of atoms from the dislocation core to the growth surface.…”

Section: Modeling Approachsupporting

confidence: 84%

Stress‐dislocation management in MOVPE of GaN on SiC wafers

Rudinsky¹,

Yakovlev²,

Lundin

et al. 2016

Physica Status Solidi (a)

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A combined experimental and modeling study of stress and curvature evolution during (0001) GaN growth on (0001) 4H-SiC wafers is presented. It is shown that the GaN layers are under the compressive stress, whose magnitude depends on the composition of the AlGaN buffer that is used to accommodate the epitaxial strain between GaN and SiC. Processing of in situ curvature measurements suggests fast relaxation of the mismatch stress in GaN when the Al content is increased. At that, nucleation of new dislocations is possible, but the dislocation density decreases rapidly over a narrow part of the GaN layer due to large inclination and annihilation of the threading dislocations. Eventually, correlations between the curvature/stress/dislocation evolution and AlGaN buffer composition can be established and optimal strategy for the growth of crack-free structures can be suggested.

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Dislocation bending and tensile stress generation in GaN and AlGaN films

Cited by 36 publications

References 31 publications

Defects in Single Crystalline Ammonothermal Gallium Nitride

Defects in Single Crystalline Ammonothermal Gallium Nitride

The influence of reactor height adjustment on properties in GaN films grown on 6H-SiC by metal organic chemical vapor deposition

Stress‐dislocation management in MOVPE of GaN on SiC wafers

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