Mg incorporation process during LP-MOVPE of InP, GaInAs and GaInAsP

Abstract

The Mg incorporation process has been studied during low pressure metalorganic vapor phase epitaxy of InP, GaInAs and GaInAsP layers. In InP a cubic increase of the carrier concentration versus Mg flow in the gas phase is observed; a maximum carrier concentration of 2 × 10 18 cm −3 can be obtained. Results from Hall measurements and low temperature photoluminescence suggest that above a critical level of 10 18 atoms/cm 3 Mg is incorporated in InP both as a substitutional acceptor and as an interstitial donor. In ternary layers and in quaternary layers with a rather high Ga content the carrier concentration exhibits a square increase versus Mg flow; a saturation at a level of approximately 1 × 10 19 cm -3 is reached. The data can be explained assuming that in Ga containing compounds, such as ternary and quaternary layers, the concentration of interstitial Mg is much lower than in InP leading to a markedly reduced Mg diffusion during growth even at high concentrations.