GaInP growth by chloride vapor phase epitaxy

Abstract

GaInP layers were grown epitaxially on GaAs substrates by chloride vapor phase epitaxy (VPE). The dependence of morphology, photoluminescence characteristics on growth temperature and composition as well as doping with sulfur, selenium, and silicon were studied. We obtained high photoluminescence emission intensity from unintentionally doped crystals and high purity crystals with a narrow FWHM, 7.4 meV at 77 K (3.8 meV at 4.2 K). The background carrier concentration of undoped Ga 0.52 In 0.48 P was estimated to be 1 × 10 15 cm -3 using samples lightly doped with sulfur. We found that the best growth temperature for undoped Ga 0.52In 0.48P was 680°C, and that the best quality crystal was obtained not when GaInP was lattice matched to the GaAs substrate at room temperature, but when the composition of GaInP was on the InP side. Doping experiments were performed using H 2S, H 2Se, and SiCl 4. GaInP electron carrier concentrations of 4 × 10 18 cm -3 were achieved by S and Se doping. When heavily doped with S and Se, the compositions of the epitaxial layers were shifted to the GaP side as compared to undoped samples grown under the same conditions. When SiCl 4 was used, high concentrations of Si were found at the interface between GaInP and GaAs. This appears to be due to the difference between the binding energy of chlorinated silane and As, and the binding energy of GaCl (or InCl) and As at the surface of the GaAs layer. Since the binding energy between the chlorinated silane and As is greater than the binding energy between GaCl (or InCl) and As, high concentrations of silicon appear at the interface between the GaInP epitaxial layers and the GaAs layer.