Modern micro- and optoelectronic semiconductor devices consist of thin multilayers grown epitaxially on a substrate. These layers must be of high crystallographic quality. Otherwise, defects present in the structure deteriorate parameters of devices and lead to their fast degradation. Very often however, there are no suitable substrates for lattice-matched epitaxy and defects are generated at the epilayer/substrate interface. To prevent their propagation to the next-grown layers of the structure the lateral overgrowth technique has been elaborated. The breakthrough in development of long lifetime cw GaN/InGaN blue lasers, being due to high efficiency of defects filtration during lateral overgrowth, is the most spectacular recent achievement of the technique.
The talk will provide a general review of the epitaxial lateral overgrowth (ELO) technology and of application of ELO layers as substrates with adjustable lattice parameter. In particular, the issues of ELO growth mechanism, defect filtration during ELO procedure and strain in ELO layers will be addressed. Recent literature data on MOVPE ELO growth of GaN on sapphire or SiC and our results on lateral overgrowth of III-V compound semiconductors (GaAs/Si, GaSb/GaAs, etc.) by liquid phase epitaxy (LPE) will be used as examples. Finally, other lateral overgrowth techniques will be presented and compared with the conventional ELO technique.