Abstract
The optimal conditions for growth of homoepitaxial InAs layers by molecular beam epitaxy were investigated over a wide range of substrate temperatures and As2/In flux ratios at a growth rate of 0.66 monolayer/s. Material quality was investigated using a variety of techniques: differential interference contrast microscopy, scanning electron microscopy, and atomic force microscopy. The results indicated that the InAs layer grown at a temperature between 430 and 450 °C with an As2/In flux ratio of about 15:1 yielded the highest quality, with a defect density of 2 × 104 cm−2 and a root mean square roughness of 0.19 nm. The quality can be further improved by growth at a lower growth rate of 0.22 monolayer/s. The morphology of large oval hillock defects on the InAs layers suggested that these defects originated at the substrate surface.
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