Electrical study of Schottky barriers on atomically clean GaAs(110) surfaces

We report here a systematic study of the electrical properties of a large number of metal/n-type GaAs (Cr, Mn, Sn, Ni, Al, Pd, Cu, Ag, Au) diodes. Diodes were fabricated on cleaved GaAs(110) surfaces under ultrahigh-vacuum conditions with in situ metal deposition. Using current-voltage (I-V) and capacitance-voltage (C-V) measuring techniques, we were able to obtain very reliable and consistent determinations of the barrier height ${\phi }_b$ and ideality factor n. All of the metal-semiconductor systems formed on lightly doped (5×${10}^{16}$/${\mathrm{cm}}^3$) n-type GaAs substrates were characterized by near-unity (1.05) ideality factors. A decrease in the effective I-V barrier height, an increase in the ideality factor in forward bias and a strong voltage dependence on the thermionic emission currents in reverse bias were found for diodes formed on the more heavily doped samples.