Beryllium ion implantation in GaAsSb epilayers on InP

Beryllium ion implantation was used to form high acceptor concentrations in GaAs1-xSbx (0.47 less than or equal to x less than or equal to 0.49) epilayers on semi-insulating InP substrates. Two implant doses were tested: Q(0) = 5 x 10(14) cm(-2) and Q(0) = 1 x 10(15) cm(-2) at an implant energy of E = 50 keV. Electrochemical profiling and secondary-ion-mass spectrometry (SIMS) results confirm acceptor concentrations of N-A greater than or equal to 1 x 10(19) cm(-3) and N-A greater than or equal to 2 x 10(19) cm(-3) within 1000 Angstrom of the GaAs1-xSbx surface for the lower and higher implant dose, respectively. These results provide a p(+) surface layer for low-resistance ohmic contact to GaAsSb-based devices. Optical microscopy and SIMS demonstrate rapid thermal anneal (RTA) temperature limits of T = 650 degrees C for Q(0) = 5 x 10(14) cm(-2) and T = 600 degrees C for Q(0) = 1 x 10(15) cm(-2). The temperature limitation is imposed by destabilization of the GaAs1-xSbx surface through Ga sputtering during implantation, and Ga and As outdiffusion during RTA. (C) 1996 American Institute of Physics.