Photo modified growth of GaAs by chemical-beam epitaxy

摘要

We report the photo modified growth of GaAs by chemical beam epitaxy at substrate temperatures in the range 335 to 670 deg using triethygallium (TEG) and arsine. A mercury-xenon lamp (electrical power 200 W) provided the irradiation for the photoassisted grwoth. The growth was monitored in real time by laser reflectometry (LR) using a 670 nm semiconductor laser, and the optically determined growth rate agreed with that obtained from the layer thickness measured by cross sectional transmission electron microscopy. The observed photo-enhancement of the growth rate at low substrate temperatures and inhibition at high substrate temperatures is thermal in origin, consistent with raising the substrate temperature by 10+- 3 deg. Cross sectional transmission electron microscopy showed that the photoassisted layers are essentially free from dislocations.