Element incorporation in GaInAsP for uniform large area MOMBE

In this study we investigated the material incorporation efficiencies in GaInAsP and InAsP layers grown on InP substrates for large area metalorganic molecular-beam epitaxy (MOMBE). We found an optimum growth temperature for the quaternary material (λG=1.55μm) around 500–510°C, since in this range the lattice matching shows a temperature coefficient of about 80–120ppm only. The P incorporation efficiency is improved with increasing growth temperatures (480–520°C). We found for InAsP and GaInAsP (λG=1.05μm) a strong reduction of the P incorporation efficiency with increasing V/III ratio, which is accompanied by a reduced P content in the layer. Additionally with this reduced P, the Ga incorporation efficiency for the quaternary material is improved. Using the same V/III and As/P ratio for the InAsP and GaInAsP material, a higher P content in the InAsP layers is achieved. The results were used as calibration data for the development of a novel type of wafer holder with improved temperature uniformity. For GaInAsP single layers (λG=1.55μm) a standard deviation in emission wavelength of |Δλ|<1.5nm was achieved. From the results for all material compositions a temperature distribution with ΔT<1°C can be inferred across a 2″ wafer.