Potential, ionized impurity, and free carrier distributions are investigated for Schottky junction under a reverse bias with an alternating component which is large compared to k(B)T/q. Nonlinear effects in the junction behavior are considered in the framework of a general large signal model as well as is in the framework of a second-order model. Free carrier distribution is assumed to be an equilibrium one and impurity ionization is treated using Shockley-Read-Hall statistics. It is shown that in the large-signal case potential, ionized impurity, and free carrier distributions are significantly different from the corresponding small-signal distributions. The proposed second-order model is shown to be accurate for the values of the fundamental of ac potential which are less or approximately equal to k(B)T/q. (C) 2003 Elsevier Ltd. All rights reserved.