The strained-layer-superlattice (SLS) consisting of undoped InAs and carbon-doped GaAs (GaAs:C) layers were successfully grown on InP substrates by LP-MOVPE. The grown superlattice shows the p-type conductivity with a hole concentration of 1 x 10(19) cm(-3) and Hall mobility of 70 cm(2) V-1 s(-1) at room temperature. The resistivity is low enough to be used as an electrically equivalent highly p-type InGaAs base layer of an InP/InGaAs heterojunction bipolar transistor (HBT). The High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF STEM) images reveal that the InAs/GaAs:C superlattice has an interface more abrupt than the undoped InAs/GaAs superlattice. It is attributed to the suppressed In diffusion from InAs to GaAs due to carbon doping in GaAs. (C) 2012 Elsevier B.V. All rights reserved.