Epitaxial Lateral Overgrowth of GaAs on a Si Substrate

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Abstract
Epitaxial lateral overgrowth (ELO) of GaAs on a Si substrate was successfully achieved by a combination of LPE and MBE. To prevent meltback of the Si substrate by Ga solution, a thin GaAs layer (2.4 µm) was grown by MBE prior to the deposition of SiO2 by P-CVD. Uniform GaAs ELO layers with mirror surface were grown through a line-shaped window cut in SiO2 film on a Si substrate with a GaAs layer. Chemical etching with an RC-1 etchant showed that there were no etch pits observed in ELO layers except in the region just over the line seed. Although cracks are observed in ELO layers due to the difference in thermal expansion coefficients between GaAs and Si, it is concluded that this technique is promising for obtaining dislocation- free GaAs on a Si substrate.