two schottky diodes were fabricated by evaporation of nickel on to an n-type cdf/sub 2/'yf/sub 3/ semiconductor. diode a was prepared on a slightly etched polished surface and diode b on an unpolished strongly etched surface. the current-voltage (i-v), capacitance-voltage (c-v), and conductance-voltage (g-v) characteristics were determined at room temperature. both diodes showed non-ideal i-v behaviour with ideality factors 1.5 and 2.0, respectively and are thought to have a metal-interface layer-semiconductor configuration. under forward bias, the admittance showed large frequency dispersion possibly caused by the interface states in thermal equilibrium with the semiconductor analysis of the c-v data in terms of lehovec's model (1966) of an interface state continuum required the supposition of two time constants differing by 2 to 3 orders of magnitude. the characteristic parameters of the interface states (energy position, density, time constant and capture cross-section) were obtained for the values of the forward bias in the range 0.0 v v 0.2 v. the diode b is found to have interface state densities about two orders of magnitude higher than the diode a which may be attributed to the different surface treatments. the c-v measurements at 100 khz also indicated the presence of a deep donor trap about 0.6 ev below the conduction band edge in diode a