Doping dependence of the schottky-barrier height of ti-pt contacts to n-gallium arsenide

The barrier height and ideality factor of Ti-Pt contacts on n-type GaAs have been measured in the doping range Nd =3.3×10 16 to 3×1018 cm -3. The flat-band barrier height, determined from capacitance-voltage measurements, is found to be independent of Nd whereas the effective barrier height for current transport, defined by the relation for thermionic emission, decreases rapidly at Nd >1×1018 cm-3. The results agree quite well with thermionic field-emission theory.