Characteristics of TiNx/n-Si Schottky diodes deposited by reactive magnetron sputtering

The effects of the substrate bias voltage and the deposition temperature on the electrical characteristics and the 1/f noise of TiNx/n-Si Schottky dio des fabricated by reactive magnetron sputtering are investigated. As the su bstrate bias voltage varies from -40 to -100 V, the ideality factor of the diodes remain almost unchanged whereas the noise intensity as a function of the current shows a shift parallel by about one order of magnitude. At low current levels, the noise intensity is proportional to the current and is attributed to the mobility and diffusivity fluctuation. At higher current l evels, the noise intensity is proportional to the square of the current and is attributed to bulk traps mainly near the interface. Analysis of the noi se measurements shows that both the Hooge parameter and the bulk trap densi ty near the interface first are increased and then decreased as the negativ e substrate bias voltage increases from 240 to -100 V. This is in contrast with the effects of the deposition temperature where we found that the Hoog e parameter remains almost constant, while both the ideality factor and the interface states density are decreased as the deposition temperature incre ases from room temperature to 400 degrees C. The trap properties of the TiN x/n-Si Schottky diodes are correlated with the stoichiometry of the TiNx fi lms investigated by spectroscopic ellipsometry measurements. (C) 1999 Ameri can Institute of Physics. [S0021-8979(99)00808-7].