Carrier profiles and electron traps at a growth-interrupted layer in GaAs fabricated by a focused ion beam and molecular beam epitaxy combined system

A thin Si-doped layer was fabricated over a laterally selected area on a mo lecular beam epitaxy (MBE)-grown GaAs surface by 200 eV or 30 keV Si focuse d ion beam (FIB) implantation and successive overlayer regrowth using an FI B/MBE combined system. Characteristics of the buried doped layer were inves tigated by means of capacitance-voltage (C-V) and deep level transient spec troscopy (DLTS) methods. It was found that irradiation damages can be reduc ed by lowering the implantation energy, and large amount of carriers were o bserved in the 200 eV Si implanted region without annealing. It was also fo und that the growth interruption induces electron traps that are located be low the midgap but has fewer effects on the activation of implanted dopants . (C) 2000 Elsevier Science B.V. All rights reserved.