Unexpected Aspects of Strain Relaxation and Compensation in InGaAs Metamorphic Structures Grown by MOVPE

Gocalinska, Agnieszka; Manganaro, M.; Pelucchi, E.

doi:10.1021/acs.cgd.6b00150

Cited by 5 publications

(12 citation statements)

References 32 publications

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“…Increasing the thickness of the AlInGaAs layer led to a higher RMS value, from ∼11 nm for the 300 nm thick layer to ∼23 nm for the AlInGaAs layer of 1400 nm thick preceded by an InGaAs strain-balancing layer. Indeed, the attempted addition of a strain-balancing layer before AlInGaAs layer deposition did not improve the surface roughness, despite showing promising results in previous works (ref ). Furthermore, the AlInGaAs compound showed a deteriorated surface with the subsequent deposition of other similar or thicker AlInGaAs layers.…”

Section: Resultsmentioning

confidence: 99%

“…The In x Ga 1– x As MBL was deposited on the GaAs buffer following a single parabolic grading profile. The design, based on a model discussed in ref , was optimized as reported in ref . The STEM HAADF image of the full laser structure (Figure b) confirmed that most of the threading dislocation network was buried down close to the GaAs substrate.…”

Section: Methodsmentioning

confidence: 99%

“…The design, based on a model discussed in Ref., 25 was optimized as reported in Ref. 26 . The STEM HAADF image of the full laser structure (Figure 1b) confirmed that most of the threading dislocation network was buried down close to the GaAs substrate.…”

Section: Methodsmentioning

confidence: 99%

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Importance of Overcoming MOVPE Surface Evolution Instabilities for >1.3 μm Metamorphic Lasers on GaAs

Mura

Gocalinska

O'Brien

et al. 2021

Crystal Growth & Design

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We investigated and demonstrated a 1.3 µm-band laser grown by metalorganic vapour phase epitaxy (MOVPE) on a specially engineered metamorphic parabolic graded InxGa1-xAs buffer and epitaxial structure on a GaAs substrate. Bottom and upper cladding layers were built as a combination of AlInGaAs and InGaP alloys in a superlattice sequence. This was implemented to overcome (previously unreported) detrimental surface epitaxial dynamics and instabilities: when single alloys are utilised to achieve thick layers on metamorphic structures, surface instabilities induce defect generation. This has represented a historically limiting factor for metamorphic lasers by MOVPE. We describe a number of alternative strategies to achieve smooth surface morphology to obtain efficient compressively strained In0.4Ga0.6As quantum wells in the active layer. The resulting lasers exhibited low lasing threshold with total slope efficiency of 0.34 W/A for a 500 µm long ridge waveguide device. The emission wavelength is extended as far as 1360 nm.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Importance of Overcoming MOVPE Surface Evolution Instabilities for >1.3 μm Metamorphic Lasers on GaAs

Mura

Gocalinska

O'Brien

et al. 2021

Crystal Growth & Design

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“…There are different chemical grading types of MB including uniform [ 15 – 17 ], step graded [ 18 – 20 ] and continuously graded [ 21 – 23 ]. The continuously graded approach could be linear [ 20 , 24 ] or parabolic [ 25 , 26 ], and generally speaking it allows more flexibility in the growth, tailoring the strain relaxation. Importantly, the parabolic profile has been shown to be less sensitive to variations in the MB thickness [ 22 ] and it has been shown to confine the defects further away from the active region [ 27 , 28 ] thus, making it a more promising approach for strain tuneability.…”

Section: Introductionmentioning

confidence: 99%

Dislocation and strain mapping in metamorphic parabolic-graded InGaAs buffers on GaAs

et al. 2023

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We investigate different architectures for parabolic-graded InGaAs metamorphic buffers grown on GaAs using transmission electron microscopy techniques. The different architectures include InGaP and AlInGaAs/InGaP superlattices with different GaAs substrate misorientations and the inclusion of a strain balancing layer. Our results correlate: (i) the density and distribution of dislocations in the metamorphic buffer and (ii) the strain in the next layer preceding the metamorphic buffer, which varies for each type of architecture. Our findings indicate that the dislocation density in the lower region of the metamorphic layer ranges between 108 and 1010 cm−2, with AlInGaAs/InGaP superlattice samples exhibiting higher values compared to samples with InGaP films. We have identified two waves of dislocations, with threading dislocations typically located lower in the metamorphic buffer (~ 200–300 nm) in comparison to misfit dislocations. The measured localised strain values are in good agreement with theoretical predications. Overall, our results provide a systematic insight into the strain relaxation across different architectures, highlighting the various approaches that can be used to tailor strain in the active region of a metamorphic laser. Graphical abstract

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“…In recent experimental work, Gocalinska et al [14] considered InGaAs/GaAs (001) stacked heterostructures consisting of combinations of uniform and parabolically-graded layers. The objective of their work was to understand strain relaxation by adjusting the nominal compositional value and/ or thickness of the buffer layer for the purpose of controlling the strain and defect densities in the device layer.…”

Section: Introductionmentioning

confidence: 99%

Strain compensation in a semiconducting device structure using an intentionally mismatched uniform buffer layer

Kujofsa¹,

Ayers²

2016

Semicond. Sci. Technol.

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The extent of strain relaxation in semiconducting device heterostructures has important implications in the design of high electron mobility transistors, light-emitting diodes, and laser diodes, in which the residual strain affects the device characteristics. In this work, we develop the theoretical framework for understanding strain compensation in a semiconductor device layer using a uniform buffer layer which can be intentionally mismatched to the material above. Specifically, we determined the critical condition for complete strain compensation in the device layer by intentionally introducing a compositional mismatch at the device-buffer interface. We present minimum energy calculations and show that for a given device layer with fixed mismatch and layer thickness, the buffer layer may be designed with the appropriate combination of thickness and mismatch such that the device layer will have zero residual strain in equilibrium. Such a structure can be referred to as a completely strain-compensated design. In the more general case, there may be partial strain compensation, and we give a simple physics-based Gaussian-type function describing the residual strain in the device layer. We have applied this general framework to In x Ga 1−x As/GaAs (001) heterostructures for the purpose of illustration, but the work is applicable to any diamond or zinc blende (001) heteroepitaxial material system.

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Unexpected Aspects of Strain Relaxation and Compensation in InGaAs Metamorphic Structures Grown by MOVPE

Cited by 5 publications

References 32 publications

Importance of Overcoming MOVPE Surface Evolution Instabilities for >1.3 μm Metamorphic Lasers on GaAs

Importance of Overcoming MOVPE Surface Evolution Instabilities for >1.3 μm Metamorphic Lasers on GaAs

Dislocation and strain mapping in metamorphic parabolic-graded InGaAs buffers on GaAs

Strain compensation in a semiconducting device structure using an intentionally mismatched uniform buffer layer

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