Organometallic growth and characterization of GaxIn1−xP (x=0.51, 0.65, 0.69)

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Abstract
The growth and characterization of GaxIn1−xP (x=0.51, 0.65, 0.69) are described in this paper. The organometallic vapor‐phase epitaxial (OMVPE) growth was carried out in an atomospheric pressure reactor using trimethylgallium (TMGa), trimethylindium (TMIn), and phosphine (PH3). GaAs and commercially available hydride vapor‐phase epitaxial GaAs0.70P0.30 and GaAs0.61P0.39 were used as the substrates. The influence of growth temperature and V/III ratio on the properties of the OMVPE epilayers was studied. This resulted in the determination of an optimum growth temperature of 625 °C and an optimum V/III ratio range of 40–50. The results of the mismatch due to the different lattice constants of the GaxIn1−xP epilayer and the substrate were investigated. It was found that high‐quality GaxIn1−xP epilayers can be obtained only when the mismatch ‖Δa/a0‖ is less than 1×10−3. Under the conditions mentioned above, epilayers were reproducibly obtained with featureless surface morphologies, and photoluminescence (PL) with high intensities and narrow half‐widths (41–43 meV at 300 K). The dislocation etch pit densities ρ of Ga0.65In0.35P and Ga0.69In0.31P epilayers were 7.4–8.6×104 cm−2, grown lattice matched to GaAs1−yPy ( y=0.30, 0.39) substrates with ρ=6.4–7.5×105 cm−2. The degradation of PL intensity after annealing at temperatures between 400 and 600 °C in H2 or N2 indicates an increase in the surface recombination velocity for GaInP epilayers. Etching 30 Å from the surface was found to restore the original PL intensity.