Impact of Group-V Gas Purging Period on a Reduction of Intermixing Layer Formation at Heterointerface of InGaAs/InP Superlattice

A non-abrupt heterointerface owing to a formation of intermixing layers in the InGaAs/InP superlattice (SL) grown by metal organic vapor-phase epitaxy has been improved by optimizing a purging period of TBP onto the InGaAs terminated surface, and TBA onto the InP terminated surface. The SL structure was analyzed by the ω-2θ results around the InP (004) symmetric plane measured by high-resolution X-ray diffraction. In order to estimate a thickness of intermixing layers, we alternatively proposed a model using Fourier transform of a periodic trapezoid-shape scattering function to fit to an intensity of high-order satellite peaks. Our results show that purging the InGaAs terminated surface with TBP for 2–4 s could effectively remove residual As atoms and reduce As carry-over in the next-grown InP layer. By purging the InP terminated surface with TBA, even though an effect of P carry-over is reduced, the SL becomes more suffered from a diffusion of As atoms into the beneath InP layer.