Stress‐induced structural changes in thin InAs layers grown on GaAs substrate

Abstract

Effect of high temperature-high pressure treatment on strain state of the lattice mismatched InAs layers grown on the GaAs substrate was investigated by means of X-ray diffraction methods. The InAs layers were grown on (100) oriented GaAs by molecular beam epitaxy. Measurements of the rocking curve width and lattice parameters were carried out using high resolution diffractometer. Annealing of the InAs/GaAs structure performed at high pressure changes its strain state and defect structure. Especially, annealing at the growth temperature at high pressure was found to be effective in improvement of the structural perfection of the layer. It means that thin InAs layers having comparatively low dislocation density can be produced by high temperature -high pressure procedure. The relative changes of threading dislocation density were sensitive to the temperature of the treatment, however they were independent of the primary defect structure of the samples.

High-quality InAs grown on GaAs substrate with an in situ micro-structured buffer

“…The narrow XRD peak with an FWHM of 320 arcsec observed from the top 200 nm InAs epilayer suggests that InAs epilayers grown by this method possess good crystalline quality. This value obtained in our study for such a thin InAs epilayer is comparable with that obtained from 5-8 mm thick InAs epilayers grown on GaAs substrate [14,15]. Fig.…”

Studies of lattice mismatch and threading dislocations in GaAs/Si grown by MBE

“…The calculated values are f m = 2.46%, ε = −1.06 × 10 −2 and γ = 0.266. For InAs/GaAs, the values of the lateral strain and the strain parameter in the InAs layers were determined as ∼ − 7.59 × 10 −4 and 0.011, respectively [6]. According to these results, it can be said that GaAs on Si is more forced than InAs on GaAs to adapt to the substrate.…”

“…When the epilayer thickness is greater than a certain critical thickness (h c ), the misfit dislocations emerge at (or around) the interface due to a large lattice mismatch between the epilayer and the substrate. And thus, they cause partial or complete strain relaxation in the structure [6][7][8]. Therefore, the misfit dislocations are an equilibrium effect for h > h c , where h is the epilayer thickness [9].…”

“…degrading the quality of the epitaxy, limiting the performance of devices, reducing mobilities and acting mid-band-gap states [2,6,9,16]. Therefore the lattice mismatch and consequently the threading dislocations in GaAs/Si films are the subject of this study.…”

“…There are several methods for reducing the dislocation density, such as substrate misorientation, buffer layers employing strained layers superlattices, postannealing of the heterostructure and selected (patterned) area growth [13][14][15]. It is also known that the high temperature annealing of heterostructures at high hydrostatic pressure (HP) of ambient gas (HT-HP treatment) causes changes in the strain state of the layer and thus the defect density in the substrate [6]. However, the reduction dislocation density in the epilayer is still an open field.…”