Misfit dislocation formation in the AlGaN∕GaN heterointerface

Floro, Jerrold A.; Follstaedt, D. M.; Provencio, Paula Polyak; Hearne, Sean J.; Lee, S. R.

doi:10.1063/1.1812361

Cited by 123 publications

(90 citation statements)

References 17 publications

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“…The dislocation with the shortest Burgers vector that lies in a pyramidal plane is, , and it is called a mixed dislocation. As shown in figure 17, it can lie in the low index , , and planes (33,34). This can also be confirmed by the fact that , where h is the glide plane represented by three indices created by dropping the i index from the {hkil} representation.…”

Section: Derivation Of Most Probable Slip Systemssupporting

confidence: 55%

“…The transmission electron microscopy (TEM) work of Srinivasan et al (33) on InGaN grown on GaN, and by Floro et al (34) who grew AlGaN on GaN strongly show that mismatch dislocations are formed in the film and are not just extensions of dislocations in the substrate. This suggests that the important factor is the magnitude of the strain independent of whether the film is in compression or tension.…”

Section: Discussionmentioning

confidence: 99%

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Control of Defects in Aluminum Gallium Nitride ((Al)GaN) Films on Grown Aluminum Nitride (AlN) Substrates

Batyrev¹,

Wu²,

Chung³

et al. 2013

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Sensors and Electron Devices Directorate, ARLApproved for public release; distribution unlimited. ii REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)February 2013 ARL-TR-6350 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACTWe present efforts aimed at establishing a multiscale approach for simulating dislocations in aluminum gallium nitride ((Al)GaN) semiconductors. We performed quantum mechanical and classical molecular dynamics (MD) simulations to study the electronic and atomic structure of threading edge and screw dislocations in AlGaN, focusing on the structure of the dislocation core and the electrical activity of dislocations, and estimating dislocation velocities as a function of applied stress and temperature. We used the calculated mobility functions from MD to study different junction configurations using a discrete dislocation dynamics (DDD) simulator, ParaDiS. Finally, we predicted the most likely slip planes in wurtzite (Al)GaN semiconductors based on general crystallographic principles. The most important results are (1) aluminum (Al) atoms do not segregate to the dislocation core and atoms in the dislocation core do not produce any defect levels in the bandgap; (2) we performed first time classical MD calculations of dislocation velocity as a function of applied stress for three slip systems in gallium nitride (GaN); (3) we adapted ParaDiS to simulate wurtzite semiconductors; and (4) the plane strain produced by the lattice mismatch during growth on the plane does not create a shear stress on the basal or prismatic planes, hence the operational slip plane must be a pyramidal plane, the most probable being the slip system. iii Contents SUBJECT TERMS

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Section: Derivation Of Most Probable Slip Systemssupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Control of Defects in Aluminum Gallium Nitride ((Al)GaN) Films on Grown Aluminum Nitride (AlN) Substrates

Batyrev¹,

Wu²,

Chung³

et al. 2013

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“…A first investigation of the SL film was performed by light microscopy (not presented here) and showed some surface roughening but no macroscopic cracks despite the fact that the film contained more than 60% Al in average and was about 400 nm thick, which is far above the critical thickness for a homogenous Al 0.6 Ga 0.4 N film grown on GaN [4,5]. However, the bright field (BF) TEM image taken along the [0 110] zone axis -shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Relaxation in crack‐free AlN/GaN superlattices

Kröger

Kruse

Röder

et al. 2006

Physica Status Solidi (b)

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An AlN/GaN superlattice structure for the use as low index material in distributed Bragg reflectors in the blue-violet spectral region was studied by transmission electron microscopy in cross section and plan view. The superlattice is found to partially relax during growth via the introduction of threading dislocations. Dislocation loops are found to form spontanously at discrete superlattice thicknesses indicating the accumulation of point defects. Such defects might hamper the light transmission in the targeted wavelength range.

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“…The Mathhews-Blakeslee (M-B) mechanism is particularly pertinent for low-misfit systems and considers a force balance where a threading dislocation propagates to the epitaxial layer generating a misfit dislocation [36]. However, relaxation by the M-B mechanism proceeds mainly by a+c mixed type threading dislocations, as has been observed in AlGaN and InGaN epilayers grown on GaN by MOCVD [37,38]. On the other hand, Bethoux and Vennegues [39] found both a and a+c-type misfit dislocations in cracked AlGaN films grown on GaN also by MOCVD.…”

Section: Thick Aln Ilsmentioning

confidence: 94%

Strain accommodation and interfacial structure of AlN interlayers in GaN

Dimitrakopulos

Kalesaki

Komninou³

et al. 2009

Cryst. Res. Technol.

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The strain accommodation mechanisms at AlN interlayers in GaN, grown by radio‐frequency plasma assisted molecular beam epitaxy, are studied using transmission electron microscopy techniques and atomistic modelling. Interlayers of various thicknesses grown within GaN epilayers deposited on both sapphire and silicon substrates have been employed. Interlayers of thickness below 6 nm do not exhibit line defects although local roughness of the upper interlayer interface is observed as a result of the Al adatom kinetics and higher interfacial energy compared to the lower interface. Above 6 nm, introduction of a‐type misfit and threading dislocations constitutes the principal relaxation mechanism. Due to strain partitioning between AlN and GaN, threading dislocations adopt inclined zig‐zag lines thus contributing to the relief of alternating compressive‐tensile elastic strain across the AlN/GaN heterostructure. The observed dislocation configurations are consistent with a model of independent motion by climb or ancillary glide in response to their localized three‐dimensional strain environment. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Misfit dislocation formation in the AlGaN∕GaN heterointerface

Cited by 123 publications

References 17 publications

Control of Defects in Aluminum Gallium Nitride ((Al)GaN) Films on Grown Aluminum Nitride (AlN) Substrates

Control of Defects in Aluminum Gallium Nitride ((Al)GaN) Films on Grown Aluminum Nitride (AlN) Substrates

Relaxation in crack‐free AlN/GaN superlattices

Strain accommodation and interfacial structure of AlN interlayers in GaN

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