Setting limits on the accuracy of X-ray determination of Al concentration in epitaxial layers

Bassignana, I.C.; Macquistan, D.A.; Streater, R. W.; Hillier, G.; Packwood, R.H.; Moore, V.

doi:10.1016/s0022-0248(96)00733-6

Cited by 22 publications

(8 citation statements)

References 44 publications

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“…Temperature dependent PR measurements were carried out by mounting the sample on the cold finger of a liquid nitrogen variable temperature cryostat, whose temperature can be varied between 85 and 330 K. The sample temperature was measured from 130 K to 300 K with a calibrated copper-constantan thermocouple in good thermal contact with the sample. The uncertainty in the temperature determination is estimated to be ± 1.5 K and the temperature stability during each spectrum was better than ±1 K. The composition of the layer was determined by the Double Crystal X-Ray Diffraction at a 0.5% accuracy rate [28].…”

Section: Methodsmentioning

confidence: 99%

Thermal expansion contribution to the temperature dependence of excitonic transitions in GaAs and AlGaAs

et al. 2004

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Photoluminescence and photoreflectance measurements have been used to determine excitonic transitions in the ternary AlxGa1−xAs alloy in the temperature range from 2 to 300 K. The effect of the thermal expansion contribution on the temperature dependence of excitonic transitions for different aluminum concentrations in the AlxGa1−xAs alloy is presented. Results from this study have shown that the negative thermal expansion (NTE) in the AlxGa1−xAs alloy, in the low temperature interval, induces a small blueshift in the optical transition energy. In the temperature range from ∼23 to ∼95 K there is a competition between the NTE effect and the electron-phonon interaction. Using the thermal expansion coefficient in the 2 -300 K temperature range, the thermal expansion contribution to GaAs, at room temperature, represents 21% of the total shift of the excitonic transition energy. After subtracting the thermal expansion contribution from the experimental temperature dependence of the excitonic transitions, in the AlxGa1−xAs alloy, the contribution to the electron-phonon interaction of the longitudinal optical phonon increases, relatively to the longitudinal acoustical phonon, with increasing Al concentration.

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Section: Methodsmentioning

confidence: 99%

Thermal expansion contribution to the temperature dependence of excitonic transitions in GaAs and AlGaAs

et al. 2004

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“…The structure was finished with a 50 Å thick GaAs film. The alloy composition was confirmed by PL and double crystal X-ray diffraction [25]. Quantum well thickness are estimated by the in situ characterization technique of RHEED (reflection high-energy electron diffraction) and by theoretical calculations.…”

Section: Methodsmentioning

confidence: 99%

Temperature dependence of excitonic transitions in AlxGa1−xAs/GaAs quantum wells

Lourenço

Dias

Duarte

et al. 2001

Superlattices and Microstructures

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“…In In x Ga 1-x As layers, the indium fraction x determines the electronic and optical behavior of devices, therefore accurate determining of the indium ratio in alloy are of great importance. HRXRD technique is a general way to measure the composition of epitaxial semiconductor compounds [19][20][21][22][23]. It is commonly calculated from Vegard's law…”

Section: Resultsmentioning

confidence: 99%

“…Interdiffusion occurs during the annealing process where constituent atoms such as In and Ga interdiffuse across the heterointerface. Because of movement of atoms in the samples, structural properties of the samples are expected to change such as the formation of inhomogeneous strain distribution inside of superlattice and at the interface [23]. Therefore, the data obtained using the ω-2θ reflections were analyzed for the out-of-plane and in-plane strains ε ⊥ and ε II , respectively.…”

Section: Ingaas Gaasmentioning

confidence: 99%

Interdiffusion phenomena in InGaAs/GaAs superlattice structures

Sarıkavak¹,

Öztürk

Mammadov

et al. 2010

Cryst. Res. Technol.

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We have studied structural properties of InGaAs/GaAs superlattice sample prepared by Molecular Beam Epitaxy (MBE) using high resolution X-ray diffractometer (HRXRD). Increasing strain relaxation and defect generations are observed with the increasing Rapid Thermal Annealing (RTA) temperature up to 775 °C. The higher temperatures bring out relaxation mechanisms; interdiffusion and favored migration. The defect structure and the defects which are observed with the increasing annealing temperature were analyzed. Firstly, the in-plane and out-of-plane strains after the annealing of sample were found. Secondly, the structural defect properties such as the parallel X-ray strain, perpendicular X-ray strain, misfit, degree of relaxation, x composition, tilt angles and dislocation that are obtained from X-ray diffraction (XRD) analysis were carried out at every temperature. As a result, we observed that the asymmetric peaks especially in asymmetric (224) plane was affected more than symmetric and asymmetric planes with lower polar or inclination angles due to c-direction at low temperature. These structural properties exhibit different unfavorable behaviors for every reflection direction at the increasing temperatures. The reason is the relaxation which is caused by spatially inhomogeneous strain distribution with the increasing annealing temperature. In the InGaAs superlattice samples, this process enhances preferential migration of In atoms along the growth direction. Further increase in the annealing temperature leads to the deterioration of the abrupt interfaces in the superlattice and degradation in its structural properties.

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Setting limits on the accuracy of X-ray determination of Al concentration in epitaxial layers

Cited by 22 publications

References 44 publications

Thermal expansion contribution to the temperature dependence of excitonic transitions in GaAs and AlGaAs

Thermal expansion contribution to the temperature dependence of excitonic transitions in GaAs and AlGaAs

Temperature dependence of excitonic transitions in AlxGa1−xAs/GaAs quantum wells

Interdiffusion phenomena in InGaAs/GaAs superlattice structures

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