PRECIPITATION IN FE-IMPLANTED OR NI-IMPLANTED AND ANNEALED GAAS

We report the formation of metal/semiconductor composites by ion impla ntation of Fe and Ni into GaAs and a subsequent anneal to nucleate clu sters. Electron diffraction experiments and high resolution transmissi on electron microscopy images indicate that these precipitates are pro bably hexagonal and metallic Fe3GaAs or Ni3GaAs with orientation relat ionship to GaAs of (10 $($) over bar$$ 10)(pp)\\(42 $$($) over bar 2)m , (0002)(pp)\\(11 $$($) over bar 1)(m), and [1 $($) over bar$$ 210](pp )\\[011](m). Correlation of the electrical and structural properties o f the samples annealed at different temperatures shows that the buried Schottky-barrier model has general applicability. (C) 1994 American I nstitute of Physics. ww $$($) over bar e