Device Degrading Interactions between Silicide Films and Bulk Defects during Rapid Thermal Annealing

Abstract

ABSTRACTThe interaction between titanium and nickel silicide films with dislocations generated at the wafer edge by thermal stress is examined in this work. The local dislocation density of the silicon wafers varied from zero to 4.8×106cm across a slice. Both titanium and nickel were deposited as thin films in the contact regions of the p-n junction diodes. Wafers were rapid thermal annealed, sequentially, for 30 s at temperatures between 300°C and 700°C. Reverse bias leakage current measurements of the as-deposited and annealed wafers were used to evaluate the impact of silicides and bulk defects on devices. A significant increase in leakage current due to the silicide/defect interaction was observed above 600 °C for both titanium and nickel. Leakage currents of devices fabricated in regions of high bulk defect density increased with the anneal temperature and dislocation density.