Effective acceptor profiles in chemically and plasma treated WNx/GaAs Shannon contacts from capacitance and current measurements

This study concerns WN_x/GaAs Schottky diodes fabricated using three semiconductor surface cleaning procedures and three temperatures for the postmetallization annealing. The electrical characteristics were interpreted on the basis of the enhanced barrier Shannon contact theory, assuming that the surface p-type dopant is provided by atoms implanted during the sputtering process or diffused during the annealing. The parameters of the effective acceptor profiles were calculated using a method where the voltage intercept of the capacitance curve and the ideality factor of the forward current characteristic are required as input data. The enhancement of the barrier after the annealing strongly depends on the surface cleaning procedure before metallization