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1Monolithic growth of GaAs templates on silicon
I. Ilkiv1*, V. Lendyashova12, D. Kirilenko3, G. Cirlin124
1- St. Petersburg State University, St. Petersburg 199034, Russia 2- Alferov University, St. Petersburg 194021, Russia 3- Ioffe Institute, St. Petersburg 194021, Russia 4- Institute for Analytical Instrumentation RAS, St. Petersburg 198095, Russia
The integration of direct-bandgap III-V material components on Si platforms have been considered as promising solutions to achieve practical on-chip light-emitting sources on Si and the implementation of Si photonic integrated circuits. The most common approach relies on the bonding of Si and III-V wafers. Although the effectiveness of the method was repeatedly demonstrated and commercial devices have been already presented, the bonding process remains complex and expensive. Therefore, utmost attention is paid toward the monolithic integration of III-V materials on Si substrates by direct epitaxial growth, which is more cost-effective and scalable. Unfortunately, due to high lattice mismatch and differences in expansion coefficients, the direct growth of III-V materials on Si substrates generally faces the challenges concerning the formation of anti-phase domains, threading dislocations, and microcracks. To obtain a high quality of material, great attention has been given to develop special tricks, including the growth of the thick buffer with several filter layers, different variations of selective area growth, utilizing of misoriented Si(100) substrates, confined epitaxial lateral overgrowth, as well as migration-enhanced epitaxy growth. Meanwhile, one-dimensional quantum dots (QDs) are known to be relatively tolerant of defects and dislocations due to the effective strain relaxation. In this regard, the use of QDs opens up the possibilities for reducing total thicknesses of GaAs buffers on Si and achieving an efficient light source.
In this study, we report on the growth of relatively thin GaAs layers of on silicon substrates by molecular beam epitaxy. Various GaAs buffer layers were grown on Si(100) and 2-4° off-axis Si(100) substrates. The impact of the growth of Si buffer layer as well as of its high-temperature annealing on the propagation of inversion boundaries in subsequently grown GaAs layers is extensively studied by atomic-force and transmission electron microscopy.
Fig.1. Cross-sectional transmission electron microscope image of QDs layer grown on GaAs/Si(100) template.
Using this GaAs buffer layers as a virtual substrates InAs/InGaAs QD in well heterostructures were fabricated (see Fig.1). Photoluminescence studies of the samples grown revealed efficient emission from InAs QDs at a wavelength of 1.25 ^m at room temperature. These results can be a major step towards monolithic integration of III-V based light-emitters on Si.
This work has been supported by the RSF grant №23-79-01117.
