Impact of the threading dislocations and residual stress on InAs islands grown on a (001) GaAs-on-Si pseudo-substrate relative to growth on standard GaAs

摘要

Strain-induced InAs islands have been grown by MBE simultaneously on a GaAs-on-Si substrate (containing a density of 10~7 threading dislocations per cm~2) and on a standard GaAs substrate (dislocation free). The impact of the substrate on the island growth mode has been examined by cross-sectional and plan-view TEM observations. Using the GaAs-on-Si substrate has resulting in the formation of a greater number of smaller islands. On the other hand, it is seen that several threading dislocations have been bent in the island plane, although the average thickness is lower than the critical thickness of plastic relaxation. Finally it is estimated that only a few percentage of the islands (less than 2percent) is affected by the threading dislocations.