Observation of in-plane asymmetric strain relaxation during crystal growth and growth interruption in InGaAs/GaAs(001)

Sasaki, Takuo*; Shimomura, Kenichi*; Suzuki, Hidetoshi*; Takahashi, Masamitsu; Kamiya, Itaru*; Oshita, Yoshio*; Yamaguchi, Masafumi*

In-plane asymmetric strain relaxation in lattice-mismatched InGaAs/GaAs(001) heteroepitaxy is studied by three-dimensional X-ray reciprocal space mapping. Repeating crystal growth and growth interruptions during measurements allows us to investigate whether the strain relaxation is limited at a certain thickness or saturated. We find that the degree of relaxation during growth interruption depends on both the film thickness and the in-plane directions. Significant lattice relaxation is observed in rapid relaxation regimes during interruption. This is a clear indication that relaxation is kinetically limited. In addition, relaxation along the [110] direction can saturate more readily than that along the [10] direction. We discuss this result in terms of the interaction between orthogonally aligned dislocations.