Thick crack‐free AlGaN films deposited by facet‐controlled epitaxial lateral overgrowth

Liu, R.; Bell, A.; Ponce, Fernando; Amano, Hiroshi; Akasaki, Isamu; Cherns, D.

doi:10.1002/pssc.200303450

Cited by 16 publications

(8 citation statements)

References 9 publications

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“…For c-plane heteroepitaxy, these slip systems experience a zero component of the stress, and are not activated. But they can be activated for growth in other orientations [9].…”

Section: Resultsmentioning

confidence: 99%

Glide along non‐basal slip planes in InGaN epilayers

Srinivasan

Geng

Ponce

et al. 2003

phys. stat. sol. (c)

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We have observed a systematic nucleation of misfit dislocations at the InGaN/GaN heterointerface. This occurs when InGaN films are grown on an epitaxially laterally overgrown GaN substrate with a reduced dislocation density. The misfit dislocations are aligned along 〈1100〉 directions forming a symmetric hexagonal array. Potential wurtzite slip systems were analysed by extending the Matthews-Blakeslee model to include Peierls forces. Due to an inactive basal plane in the c-growth direction, non-basal slip is necessary for plastic relaxation. The active slip system was identified to be {1122} 〈1123〉. The possibility of activation of other slip systems is also discussed. However, such a periodic nucleation of misfit dislocations has not been observed in InGaN alloys. These materials undergo strain relaxation usually by forming the so-called V-defects, which nucleate from the threading dislocations in the GaN substrate [4]. Misfit dislocations are observed for higher indium compositions ([In] > 1 0%), but these are random and do not provide a systematic strain relief. Lattice strain can severely affect the properties of InGaN [5] and it is important to obtain a clear understanding of strain relaxation mechanisms.In this work, we have observed a systematic strain relief in InGaN by growing the films on GaN substrates with reduced dislocation density. To our knowledge this is the first such observation in these materials. This was achieved by using epitaxially laterally overgrown GaN (ELOG) substrates. The formation of the misfit dislocations for various slip systems is analysed by extending the MatthewsBlakeslee model [1] to include the effect of Peierls forces. The active slip system was identified to be {1122}〈1123〉. We show that in the c-plane heteroepitaxy configuration the basal-plane glide is inactive. Under these conditions, non-basal glide along {1122} slip planes is activated. The possibility of other slip systems being activated is also discussed.

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“…For c-plane heteroepitaxy, these slip systems experience a zero component of the stress, and are not activated. But they can be activated for growth in other orientations [9].…”

Section: Resultsmentioning

confidence: 99%

Glide along non‐basal slip planes in InGaN epilayers

Srinivasan

Geng

Ponce

et al. 2003

phys. stat. sol. (c)

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“…The clear dark contrast line (marked as "1") corresponds to the large TD density with Burgers vectors on the basal plane, which is associated with lattice misfit relaxation. 61 A second set of dislocations of the same nature was observed on inclined boundaries within the AlGaN layer (marked as "2"). These misfit dislocations are closely related to regions with significantly large variations in Al composition.…”

Section: Dislocation and Morphology Analysismentioning

confidence: 95%

GROWTH AND ELECTRICAL/OPTICAL PROPERTIES OF Al_xGa_1−xN IN THE FULL COMPOSITION RANGE

Yun

2006

III-Nitride Semiconductor Materials

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The material development of ternary alloy, AlGaN, is key to GaNbased device applications. This chapter includes a technical review of the key issues such as growth techniques suitable for AlGaN, microstructural analyses for extended defects and cracks accompanied with growth on foreign substrates, and the electrical and optical properties of AlGaN epitaxial films. Growth methods for the full range control of AI mole fraction in AlGaN have been introduced, together with a detailed discussion of bowing parameters in association with the determination of alloy band gap as a function of Al mole fraction.

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“…Thus the sticking coefficient of aluminum adatoms on the (0 0 0 1) surface is higher resulting in a higher Al incorporation. On the other hand, the 1 12 2 À Á facet is at least partially relaxed, [12] whereas the AlGaN grown on the c-plane GaN will be under tensile strain. This strain factor if it exists alone should result in lower Al incorporation on the c-plane GaN.…”

Section: Article In Pressmentioning

confidence: 99%

Al incorporation in AlGaN on and (0001) surface orientation

Zhou¹,

Chua

Chen

2006

Journal of Crystal Growth

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Thick crack‐free AlGaN films deposited by facet‐controlled epitaxial lateral overgrowth

Cited by 16 publications

References 9 publications

Glide along non‐basal slip planes in InGaN epilayers

Glide along non‐basal slip planes in InGaN epilayers

GROWTH AND ELECTRICAL/OPTICAL PROPERTIES OF Al_xGa_1−xN IN THE FULL COMPOSITION RANGE

Al incorporation in AlGaN on and (0001) surface orientation

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Thick crack‐free AlGaN films deposited by facet‐controlled epitaxial lateral overgrowth

Cited by 16 publications

References 9 publications

Glide along non‐basal slip planes in InGaN epilayers

Glide along non‐basal slip planes in InGaN epilayers

GROWTH AND ELECTRICAL/OPTICAL PROPERTIES OF AlxGa1−xN IN THE FULL COMPOSITION RANGE

Al incorporation in AlGaN on and (0001) surface orientation

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GROWTH AND ELECTRICAL/OPTICAL PROPERTIES OF Al_xGa_1−xN IN THE FULL COMPOSITION RANGE