How thin can we make square profiles in InP/GaInAs/InP wells by organometallic vapor phase epitaxy? X-ray CTR scattering measurements

The InP/Ga_0.47In_0.53As/InP structures were grown on InP [001] substrates by low-pressure organometallic vapor phase epitaxy and analyzed by X-ray crystal truncation rod scattering measurement. The thickness of the GaInAs well layers were varied from 3 to 30 monolayer (ML) to find to which thickness the square profiles of the quantum wells can be made. The growth temperature was set at 620 °C. The results indicated that the threshold layer thickness to make the peak compositions as designed was between 10 and 15 ML with the growth conditions adopted here. It suggests that it is very difficult to obtain an ideal quantum well structure of a few MLs as designed. The GaInAs layer should be thicker than a few 10 MLs to obtain the peak compositions as designed.