Reflection high-energy electron diffraction intensity oscillation study of InGaAs and InAlAs on InP: Application to pseudomorphic heterostructures

This letter reports the first reflection high-energy electron diffraction intensity oscillation study of strained, pseudomorphic In_1-xGa_xAs and In_1-yAl_yAs grown by molecular beam epitaxy on InP substrates. Strain-induced effects are studied over a broad range (up to 3%) of positive and negative mismatch. During mismatched growth, an abnormal damping of the oscillation intensity is seen which leads to the identification of a threshold thickness above which monolayer by monolayer growth no longer occurs during uninterrupted growth. This thickness is about a factor of 5 smaller than recently calculated and measured values of the critical thickness at which dislocations appear. This observation is believed to have important implications for the growth of pseudomorphic devices.