Modification of Surface State Density Distribution of p-InP Surfaces by Nitrogen Radical Exposure

Surface state density distributions of p-InP surfaces before and after nitrogen (N 2 )-radical exposure were characterized using an air-gap capacitance–voltage ( C – V ) technique. Before N 2 -radical exposure, a discrete level with a high density and extremely slow electron capture rate existed, causing strong Fermi level pinning. The peak density and full width at half maximum of this level were estimated. After N 2 -radical exposure, the density of the discrete level decreased to (5–6) × 10 12 cm -2 eV -1 . On the other hand, the continuous level became to be observed. Furthermore, the electron capture rate of the discrete level became larger after the N 2 -radical exposure.