Barrier heights of Schottky junctions on n-InP treated with phosphine plasma

Surface treatment of n-InP by phosphine (PH 3 ) plasma is carried out to modify the surface properties. It is observed from Kelvin probe measurements that the surface Fermi level shifts near the conduction band edge after PH 3 plasma treatment, while the surface Fermi level is located around 0.4 eV below the conduction band edge for a surface wet-etched before PH 3 plasma treatment. A funneling metal-insulator-semiconductor (MIS) Schottky structure is formed on PH 3 -plasma-treated InP to evaluate the treated surface. The Schottky barrier height evaluated from the Richardson plot is found to depend strongly on the metal work function. This suggests that the surface state density pinning the surface Fermi level is profoundly reduced due to PH 3 plasma treatment.