Investigation of parameters of Schottky diodes based on chromium silicides

Abstract

In this work, the parameters of Schottky diodes obtained by sputtering chromium on silicon and annealed at 900÷1100°C. were investigated. Experimental studies of Schottky contacts based on silicides have an all-microscopic analysis of the physical and chemical properties of the layers and an analysis of the electrical behavior of the system. The Schottky model assumes that surface states are located on the border between the transition layer and silicon. Using measurements of direct and inverse volt-amperage characteristics (VAC), values of the height of the effective Schottky barrier, the rate of change in the height of the barrier, as well as the value of the density of surface states, the thickness of the transition layer were obtained and the tunneling process was considered. The temperature dependencies of electrical conductivity are given and the course of the curve is analyzed. The obtained VAC is explained by the model of thermionic emission of the Schottky theory. Height of a barrier to contact chrome-silicon silicide which is equal to 0.65 eV is determined, and the factor of ideality was close to unit. The number of steps required by the charge carriers to overcome the potential barrier is determined. It is described that the current transfer mechanism is associated with the presence of surface states at the interface, as well as the occurrence of lattice mismatch and the difference in thermal coefficients. Diode illumination by LED confirms the effect of surface states on VAC. An increase in the surface states of photogenerated holes is shown. It has been shown that the existence of surface states affects the change in the height of the potential barrier, the amount of bending of the zones, and also determines that the predominant transfer mechanism is a tunneling multistage mechanism.