The effective density of interface states that exist at the metal–semiconductor Schottky barrier formed between W–Ti and silicon implanted (n‐type) GaAs has been characterized using forward‐biased capacitance–voltage (C–V) measurements. The Schottky diodes were fabricated by sputtering from a tungsten titanium target under different nitrogen gas ambients of 0%, 6%, and 12%. The nitrogen incorporation and interface stability were verified by secondary ion mass spectroscopy (SIMS) and Rutherford backscattering (RBS). The results of this study clearly show that the lowest effective density of interface states was obtained for the highest nitrogen ambient of 12% at a deposition rate of 10 nm/min.