Current controlled liquid phase epitaxial (CCLPE) growth of InGaAs on (100) InP

Abstract

High quality epitaxial layers of In_xGa_1−xAs (x = 0.53) were grown on semi-insulating (Fe-doped) (100) InP sub-strates. The layers were grown at a constant furnace temperature of 640°C by passing a direct electric current (0–10A/cm²) from the substrate to the melt. In order to minimize the out-diffusion of Fe atoms from the bulk of the substrate during the melt saturation, the substrate was kept at a cold temperature region (340°C) within the growth chamber and remotely loaded in the graphite boat just prior to the initiation of the growth cycle. In addition to pre-venting the out-diffusion of Fe atoms, this procedure sub-stantially reduced the thermal degradation of the InP sub-strate surface. The above technique produced high quality layers having uniform thickness and good surface morphology. A study of the dependence of growth rate on the applied current density yielded an average growth rate of 0.06µm/ A-min. Room temperature Hall measurements on layers grown by CCLPE resulted in Hall mobilities µ₃₀₀ = 8900cm²/V-sec at a carrier concentration of 6.2 × l0¹⁶cm⁻³. The improve-ment in the mobility achieved by the CCLPE technique is attributed to a reduced out-diffusion of scattering centers from the substrate into the growth layer, as well as to the higher quality of epitaxial layers normally achieved by CCLPE.