Optical properties of InGaAs linear graded buffer layers on GaAs grown by metalorganic chemical vapor deposition

Abstract

Growth of high quality Al0.22Ga0.78As layers on Si substrates by metalorganic chemical vapor deposition

Characterization of InGaAs/InP single quantum well structure on GaAs substrate with metamorphic buffer grown by molecular beam epitaxy

“…The material schemes of the graded buffer studied include InGaAs [1][2][3], InAlAs [4][5][6], InGaP [7] and quaternary alloys such as AlGaInAs [8] and AlGaAsSb [9]. The metamorphic HEMT devices using the graded buffer have demonstrated good performance and have been applied in the circuit applications [10,11].…”

Low-Temperature and Metamorphic Buffer Layers

“…Recently this method has been extended to include the profiling of dislocation densities [90,91]. This is the case for the HRXRC of Figure 25.2, measured from an overshoot step-graded In x Al 1Àx As structure 25 As layer was grown on top of the step-graded buffer. In some step-graded layers, though, a separate peak may be resolved for each layer, and it becomes possible to extract approximate strain data directly from the peak positions.…”

“…Buffer layers with linearly-graded composition, and therefore lattice constant, have been extensively investigated in a number of material systems, including In x Ga 1Àx As/GaAs [25,26,51,[96][97][98][99][100][101][102][103][104], In x Al 1Àx As/GaAs [34,75,103,[105][106][107][108][109][110], In x Al y Ga 1ÀxÀy As/GaAs [18,19,23,35,80,95,111], Si 1Àx Ge x /Si [112][113][114][115][116], In x Ga 1Àx P/GaAs [117][118][119], In x Ga 1Àx P/ GaP [120], ZnS y Se 1Ày /GaAs [102,121], and In x Ga 1Àx Sb/GaSb [122,123]. A possible advantage of continuous grading is that layer-by-layer growth may be maintained without the intrusion of island growth associated with large, abrupt changes in composition [119].…”

“…Figure 25.10 illustrates the application of MOSS to a linearly graded In x Al 1Àx As/GaAs (001) structure grown by MBE with overshoot. The overshoot design, frequently used in linearly graded metamorphic buffers [25,26,95,128,129], is intended to allow unstrained growth of the uniform layer, but the linear change in average stress during its growth shows that exact lattice matching was not achieved. 10(b) shows the stress-thickness product as a function of thickness, and Figure 25.10(c) illustrates the average stress as a function of layer thickness [75].…”

“…Similar to other metamorphic buffers, those with linear grading usually exhibit straininduced surface roughening which may take the form of corrugations [25], crosshatch [51], or sometimes irregular surfaces. Cross-hatch is associated with misfit dislocations, and may be present in high-quality material with threading dislocation densities below the detection limit by PVTEM [103].…”