LOW-TEMPERATURE GROWTH OF HIGHLY DOPED GAAS-SI BY ATOMIC LAYER MOLECULAR-BEAM EPITAXY

Two-dimensional growth kinetics characteristic of atomic layer molecul ar beam epitaxy allows to extend the range of GaAs growth conditions t o low temperatures while preserving excellent crystallinity and layer morphology. In this work we have used ALMBE technique to obtain GaAs l ayers highly doped with silicon at substrate temperatures from 200 to 400-degrees-C. At these low growth temperatures donor incorporation is excellent and electron densities of 2 X 10(19) cm-3 were reached, lim ited by the pinning of Fermi level at the DX level. Samples exhibit pe rsistent photoconductivity due to the existence of a DX level resonant with the conduction band.