Effective Acceptor Profiles in Chemically and Plasma Treated WNx/GaAs Shannon Contacts from Capacitance and Current Measurements
Abstract
This study concerns WNx/GaAs Schottky diodes fabricated using three semiconductor surface cleaning procedures and three temperatures for the post-metallization 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, which are the surface concentration, the maximum penetration depth, and the total amount of acceptors per unit area, were calculated by means of 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. © 1991 IEEE