Fabrication of a prototypeGa0.47In0.53As/Al0.48In0.52As/InPdouble heterojunction bipolar transistor employing an embeddedn+/n−-InP:Si subcollector/collector region in an otherwise semi-insulating InP:Fe substrate was studied. The basic layer structure was accomplished by two sequential growth cycles on the basis of device qualityAl0.48In0.52As/Ga0.47In0.53Asgrown by molecular beam epitaxy (MBE) and InP grown by metalorganic molecular beam epitaxy (MOMBE). For the first time the embedded collector was implemented by truly selective infill growth into a substrate groove with vertical sidewalls defined by reactive ion etching (RIF) using MOMBE. Excellent layer morphology in combination with lateral interfaces without growth irregularities at the lateral substrate/collector interface were achieved in the [0-1-1] direction, while some minor facet formation due to slightly enhanced growth rates appeared in the [0-11]direction. The device layer stack was completed by large areaAl0.48In0.52As/Ga0.47In0.53AsMBE regrowth due to its ability to highly Be dope the GaInAs base when grown at reduced growth temperatures. Functional devices were obtained. Some degradation in the output characteristics could be directly correlated with inhomogeneities in the MBE regrown structure.