Low frequency noise in Schottky barrier contacts of titanium nitride on n-type silicon

The electrical characteristics and the low frequency noise of TiNx Schottky contacts on n-type Si(100) have been systematically measured. The TiNx thin films were deposited by reactive magnetron sputtering at room temperature. Based on a model of a parallel combination of an ideal diode of current I-1 and a generation-recombination diode of current I-2, we have extracted the contribution of both diodes to the measured total current I. Treating the two components I-1 and I-2 as different noise generators, we have analysed the observed white noise at high frequencies and the 1/f excess current noise at lower frequencies. The white noise is explained by using a pure shot noise for the component I-1, by applying Gupta's general theorem on noise in non-linear driven devices for the component I-2 and by considering an additional noise generator with a Nyquist-type intensity. The 1/f excess current noise S-I is explained by a model based on fluctuations of the generation-recombination current I-2 only. Analysis of the S-I versus I data allowed us to determine the interface state density.