Growth of AlInAs and heterostructures on InP by OMVPE

Abstract

AlInAs epilayers and GaInAs/AlInAs quantum well structures were grown on InP substrates by organometallic vapor phase epitaxy (OMVPE) using trimethylaluminum, trimethylindium, triethylgallium and arsine in a vertical reactor at reduced pressure. A smooth and flat surface was achieved at a substrate temperature of around 650°C. From double crystal X-ray rocking curves, a narrow linewidth of 24 arc sec was obtained from a 1 μm thick AlInAs epilayer, where that of the InP substrate was 14 arc sec. The variation of the lattice mismatch of the AlInAs epilayer with respect to the InP substrate was less than 5 × 10−4 across a 2-inch diameter substrate. In photoluminescence (PL) measurements at 4.2 K, an excitonic transition with a linewidth of 12 meV was observed from the AlInAs epilayer grown at 650°C with a high V/III ratio of 225. This linewidth is the narrowest ever reported for the AlInAs epilayer grown by OMVPE. We also observed a strong and narrow emission from PL measurements for a GaInAs/AlInAs single quantum well as thin as 6 Å with an energy shift of 645 meV from a GaInAs bulk bandgap at 4.2 K. Further, we obtained an excellent uniformity of single quantum wells evaluated by PL peak energy fluctuation across a 2-inch diameter substrate. In the doping study for AlInAs epilayers using disilane, an improved doping efficiency was achieved at a higher V/III ratio. The doping efficiency in AlInAs had a larger dependence on the substrate temperature than that in GaAs.