Influence of Be doping on the structural properties of low-temperature grown GaAs

The influence of Be doping on the limitations to perfect epitaxial growth of LT-GaAs is investigated by transmission electron microscopy. Be doped GaAs films with doping levels up to 1.5 10/sup 21/ cm/sup -3/ were grown by molecular beam epitaxy at 190/spl deg/C to 250/spl deg/C. In general the Be doped films seem to grow with high perfection. The roughening of the growth front is not as pronounced as in undoped material, resulting in a larger defect-free layer thickness. Even very high Be doping levels of 8 10/sup 20/ cm/sup -3/ do not show any structural defects. However, if the Be doping level is increased to 1.5 10/sup 21/ cm/sup -3/, high densities of stacking faults and precipitates are observed, although the film maintains a perfect crystallinity.