Formation of Thin GaAs Buffer Layers on Silicon for Light-Emitting Devices

Abstract

The experimental data on the growth processes of GaAs layers on silicon substrates by molecular beam epitaxy are presented. The formation of a buffer Si layer in a single growth process has been found to significantly improve the crystalline quality of GaAs layers formed on its surface and to prevent the formation of antiphase domains on both off-cut toward the [110] direction and singular Si(100) substrates. It has been demonstrated that the use of cyclic thermal annealing at temperatures 350–660°C in the flow of arsenic atoms makes it possible to reduce the number of threading dislocations and increase the smoothness of the GaAs layers surface. Possible mechanisms that lead to improvement in the quality of the surface layers of GaAs are considered. It is shown that for the thus obtained GaAs layers of submicron thickness on singular Si(100) substrates the mean square surface roughness is 1.9 nm. The principal possibility of using thin GaAs layers on silicon as templates for forming on them light-emitting semiconductor heterostructures with active area based on self-organizing InAs quantum dots and InGaAs quantum well is presented. It is found that the resulting materials exhibit photoluminescence at an emission wavelength of 1.2 µm at room temperature.