Defect study of MOVPE-grown InGaP layers on GaAs (original) (raw)
Related papers
Physica Status Solidi (c), 2007
The presence of interlayers at the inverted GaAs-on-InGaP interfaces in MOVPE grown InxGa1–xP/GaAs heterojunctions has been evidenced by (200) dark field (DF) transmission electron microscopy and high resolution X-ray diffraction. A relatively large negative strain is associated with the interlayers. Analysis of the kinematical DF contrast has allowed to establish which kind of InxGa1–xAs1–yPy compound the interlayer can be made of and the possible ranges for the compositions x and y. The localization of the interlayer at the bottom of the GaAs layer and inside it would suggest that its formation can be due to the incorporation into GaAs of P atoms remained in the reactor after PH3 was switched off and In carry-over. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamical analysis of abrupt interfaces of InGaP/GaAs and GaAs/InGaP heterostructures
2005
Interfaces between arsenide and phosphide III-V semiconductors have shown to be one of the most difficult issues to be understood and definitively solved. This problem is particularly relevant with Vapour Phase Epitaxy (VPE) and Metallo-Organic Vapour Phase Epitaxy (MOVPE) techniques, since an irreproducibility in preparing abrupt interfaces between arsenide and phosphide has been evidenced. Several researchers have ascribed this problem to the volatility of arsenic and phosphorus species and since then for long time different recipes and growth procedures have been suggested in order to obtain sharp transition between the two different materials. In this work the film/substrate interface is modelled using thermodynamical calculations after the regular solution model proposed by Jordan and Ilegems: PH 3 flows over GaAs surface, and as a consequence the substrate is enriched with P, with the formation of a thin layer of GaAsP and mixed AsP gaseous species. Samples of InGaP on GaAs substrate were grown by MOVPE and characterised by Secondary Ion Mass Spectroscopy (SIMS) and Transmission Electron Microscopy (TEM) in order to support the theoretical findings.
Direct MOVPE growth of InP on GaAs substrates
Journal of Crystal Growth, 1988
We have been able to develop a new useful method for the heteroepitaxial growth on a highly lattice-mismatched substrate by MOVPE successfully. We have found that the surface morphology of InP epitaxial layer grown on a GaAs substrate by MOVPE strongly depends on the supply rate of the group III material. Based on this experimental finding, an lnP epitaxial layer with a uniform and mirror.smooth surface has been successfully grown on a 2-inch GaAs (100) substrate. In addition to the surface morphology, we have measured the RHEED pattern, the x-ray diffraction pattern, the Hall mobility, the carrier concentration, and the photolurninescence as functions of the flow rate of the group 1II carrier gas.
Optical characterization of MOVPE grown -InAs layers in GaAs
Physica Status Solidi (c), 2005
Optical properties of various MOVPE grown structures containing InAs δ-layers in GaAs were investigated by photoluminescence, photocurrent and photomodulated reflectance spectroscopy. Observed ground and high-order interband transitions were interpreted by simulation of electronic states in InAs δ-layers using the theoretical model accounting for influence of stress and quantum states coupling. It is shown, that material parameters crucial for optimization and growth control of InAs δ-layers structures, such as equivalent layer thicknesses/compositions, can be extracted from obtained optical data. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of InGaP/GaAs heterointerfaces grown by metal organic vapour phase epitaxy
Journal of Crystal Growth, 2000
In GaAs/InGaP/GaAs structures grown by metal organic vapor-phase epitaxy (MOVPE), the two heterointerfaces are not identical. Normal photoluminescence (PL) features corresponding to the band gaps of GaAs and InGaP are seen for InGaP layer grown on GaAs. However, an intense long-wavelength feature is observed if we grow GaAs on InGaP (inverted structure) while the features of InGaP and GaAs are suppressed. The nature of interfacial regions is investigated by using di!erent gas switching sequences, which can in#uence the interfacial region composition. Signi"cantly, we "nd anomalous PL features similar to those observed in the case of inverted structure if we brie#y interrupt the growth of InGaP on GaAs and introduce AsH during the growth interruption. Secondary-ion mass spectrometry (SIMS) measurements and preliminary results of the compositional analysis of the interfacial layers based on high resolution X-ray di!raction (HRXRD) and PL measurements suggest that a deleterious e!ect arises with the exposure of InGaP surface to AsH and is attributed to the formation of an interfacial InGaAsP layer.
Deep levels in p-type InGaAsN lattice matched to GaAs
Applied Physics Letters, 1999
BSTRACT HAR 1 !3 Kk3!l Deep level transient spectroscopy (DLTS) measurements were utilized to investi ate deep level bsTl defects in metal-organic chemical deposition (MOCVD)-grown unintentionally doped p-tie InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the bandgap, with a dominant hole trap at &+O. 10 eV. Postgrowth annealing simplified the deep level spectra, enabling the identification of three distinct hole traps at 0.10 eV, 0.23 eV, and 0.48 eV above the valence band edge, with concentrations of 3.5x1014 cm-3, 3.8x10*4 cm-3, and 8.2x1014 cm-3, respectively. A direct comparison between the as-grown and annealed spectra revealed the presence of an additional midgap hole trap, with a concentration of 4x 1014cm-3 in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material quality and minority carrier properties after anealing. Of the four hole traps detected, only the 0.48 eV level is not influenced by annealing, suggesting this level maybe important for processed InGaAsN devices in the future.
Applied Surface Science, 2004
Lattice-matched, single and multiple InGaP/GaAs/InGaP quantum wells (QWs) were grown at 600 8C by low-pressure metalorganic vapour phase epitaxy (LP-MOVPE), with the use of the tertiarybuthylarsine (TBAs) and tertiarybuthylphosphine (TBP) group-V sources. In order to enhance the interface abruptness, different gas switching sequences were exploited during the growth of the interface, and the best results were obtained by inserting a few monolayer-thick GaAsP interlayers (IL), at the direct GaAs-on-InGaP interface. Low-temperature photoluminescence (PL), high resolution X-ray diffraction, transmission electron microscopy and photoreflectance spectroscopy analysis were performed on the grown heterostructures, to correlate the adopted growth sequence with the interface properties and the QW optical transitions.
Thermal annealing behaviour of deep levels in as-grown p-type MOCVD GaAs
Physica B: Condensed Matter, 2009
Thermal annealing behaviour of deep levels in p-GaAs grown by metal-organic chemical-vapor deposition (MOCVD) has been studied by deep level transient spectroscopy (DLTS) technique. Thermal annealing is found to introduce at least six new defects, four majority-carrier emitting deep levels, situated at E v +0.11, E v +0.27, E v +0.44 and E v +0.89 eV in the bandgap, and two minority-carrier emitting defects, at E c À0.49 eV and E c À0.99 eV. The minority-carrier emitting band of deep levels around $100 K in the as-grown material has also been found to resolve into two distinct peaks corresponding to deep levels at E c À0.16 eV and E c À0.21 eV, upon isochronal annealing. Four of the annealed-in defects at E v +0.27, E v +0.44, E c À0.16 eV and E c À0.49 eV are identified with previously reported deep levels, while the other four defects cannot be identified with any of the deep levels reported in the literature. Data on the annealing behavior and other characteristics of these annealed-in levels are presented. The thermal annealing behavior of the both inadvertent levels observed at E v +0.55 eV and E v +0.96 eV suggests that these levels are most likely related to arsenic antisite, As Ga , defects.