Influence of growth rate and temperature on InP/GaInAs interface structure analyzed by X-ray CTR scattering measurement

Most of high performance III-V compound semiconductor devices are fabricated utilizing heterostructures. However, when the heterostructures are grown by OMVPE, a compositional grading arises at a hetero-interfaces. The compositional grading may deteriorate the performance of the compound semiconductor devices. We have investigated the degree of the compositional grading at the interfaces using X-ray crystal truncation rod (CTR) scattering measurement. The X-ray CTR scattering measurement is a powerful technique to investigate the buried interfaces and determine the distributions of atoms quantitatively at an atomic-scale. In this work, we studied on the distributions of group-III atoms at InP/GaInAs interfaces grown by OMVPE with different growth rates, focusing on the influence of the exchange reaction of the group-III atoms near the surface during the growing. The experimental results showed that the degree of distributions of Ga atoms increased with the decrease of the growth rate. It suggested that the distribution of Ga atoms at interfaces were influenced by the exchange reaction. In order to discuss the exchange reaction, a calculation to simulate the distribution of Ga atoms was conducted considering potential energy of Ga in InP layers. The results showed that Ga atoms should exchange during the growth in top-most 3 atomic layers.