Growth of InGaP on GaAs using gas-source molecular-beam epitaxy

Abstract

The growth of high-quality InGaP films lattice matched to (100) GaAs substrates by gas-source molecular-beam epitaxy is reported. InxGa1−x P alloys were grown using a P2 molecular-beam produced by thermal decomposition of PH3 at 900 °C in a low-pressure cracking oven, and the composition x was varied from 0.48 to 0.61 using conventional effusion ovens for the In and Ga sources. Sharp (2×1) reflection high-energy electron diffraction patterns were observed during InGaP growth, and smooth surface morphology and a lattice mismatch of <1×10−4 was obtained. Using the optimum growth conditions of a PH3 flow rate of 7.6 standard cm3/min (sccm) and a substrate temperature of ∼490 °C at a growth rate of 0.5 μm/h, InGaP films were found to exhibit low-temperature photoluminesence linewidths as small as 11 meV, x-ray rocking curve linewidths as narrow as 20 arcsec, and electron mobilities similar to that reported for other epitaxial growth techniques.