GaAs(C)/InAs superlattices grown by MOMBE

Carbon is an attractive p-type dopant for III-V semiconductors due to its thermal stability relative to Be or Zn. However, it has been shown to activate as an acceptor rather poorly in In/sub 0.53/Ga/sub 0.47/As due to the relative weakness of the In-C bond. One method for overcoming this problem is growth of short-period GaAs(C)/InAs superlattices in which carbon is introduced only in the GaAs and the InAs is left nominally undoped. Using this approach, the authors have achieved hole concentrations up to 7*10/sup 19/ cm/sup -3/ with hole mobilities of 20 cm/sup 2/-V/sup -1/ sec/sup -1/. Such structures are stable against rapid thermal annealing (10 s) up to 750 degrees C. The surface morphologies are specular even for very thick (0.95 mu m) layers, and remain so even after annealing at 750 degrees C. Because of the high carrier concentration and good thermal stability, these structures show great promise for applications to InP-based lasers and heterojunction bipolar transistors.< >