Microbeam high-resolution x-ray diffraction in strained InGaAlAs-based multiple quantum well laser structures grown selectively on masked InP substrates

Abstract

Structural and optical properties of the InGaAlAs-based multiple quantum well (MQW) 1.3μm laser structures produced on InP (001) substrates by metal organic vapor phase epitaxy (MOVPE) technique in the regime of selective area growth (SAG) have been studied. An x-ray beam of 10μm diameter generated by a microbeam high-resolution x-ray diffraction (μ-HRXRD) setup based on an imaging one-bounce capillary optic and a three-bounce channel cut Si(004) analyzer crystal has been utilized to measure the diffraction curves from MQW structures grown between oxide mask stripes. The high angular resolution achieved in our experiments allowed accurate measurements of θ–2θ scans over a broad range of angles that was necessary for utilization of fitting algorithms for quantitative analysis of the strain and thickness of individual layers in the MQW structures. The thickness and strain variations in the quantum well and the barrier layers of the MQW SAG structure have been analyzed as a function of the oxide mask width in the range of 15–140μm with the gap between the oxide masks in the range of 15–80μm. Dramatic structural changes from the perfect quality MQW’s in the SAG structures with the narrow oxide masks (less than 45μm) to the strain relaxed MQW’s in the SAG regime with the wide oxide masks (more than 50μm) have been experimentally detected. The spontaneous photoluminescence emission between 1.3 and 1.51μm from the simultaneously grown InGaAlAs-based MQW SAG laser structures have been measured. Using a combination of μ-HRXRD results with the microphotoluminescence data, the optimal SAG mask parameters for the growth of integrated InGaAlAs-based optoelectronic light-emitting components and devices have been determined.

Modeling and characterization of AlGaInAs and related materials using selective area growth by metal-organic vapor-phase epitaxy

“…This implies that in our growth conditions, aluminum has a shorter diffusion length than gallium. This is in contradiction with previous reports of a longer diffusion length for Al precursor than for Ga and In ones [4,11]. Fitting the experimental thickness profiles for InP, GaAs (Fig.…”

“…2) and GaAlAs (Fig. 3 reported in the literature [1,4,7,8]. Diffusion length of Al is 50 mm, intermediate between that of In and Ga.…”

“…Therefore, the superior characteristics expected for AlGaInAs-based devices have generated a renewed interest for a well-known monolithic integration technique, namely selective area growth (SAG) [1][2][3], applied to AlGaInAs materials. In addition to specific difficulties of the SAG technique, it is certainly more complex to predict and control the diffusion variations of three III-elements (AlGaInAs) [4,5] rather than two (GaInAsP) [1,[6][7][8] in the SAG regime. Therefore the SAG technique has been much more investigated for the GaInAsP system than for the AlGaInAs one.…”

Growth of InGaAs nanowires by selective-area metalorganic vapor phase epitaxy

“…Furthermore, the enhancement of the growth rate for small d is larger for larger values of x supply . This is in contradiction with the fact that the diffusion length is longer for In than Ga [9]. We also have found that the vertical growth rate is enhanced for shorter a (data not shown).…”

Micro-Raman for compositions characterization of selective area growth of AlxGayIn1−x−yAs materials by metal-organic vapor-phase epitaxy

“…In the selective area growth (SAG) regime, the surface of analysis is limited to some tens of microns and as a result the characterization technique must have a spatial resolution in the micron range. Therefore, only few techniques have been used to analyze the SAG growth, for instance microphotoluminescence [2] and micro-X-ray diffraction (XRD) [2,3].…”