The barrier height and ideality factor of Ti–Pt contacts onn‐type GaAs have been measured in the doping rangeNd=3.3×1016to 3×1018cm−3. The flat‐band barrier height, determined from capacitance‐voltage measurements, is found to be independent ofNdwhereas the effective barrier height for current transport, defined by the relation for thermionic emission, decreases rapidly atNd>1×1018cm−3. The results agree quite well with thermionic field‐emission theory.