Thermally stable tantalum nitride/silicon Schottky barriers

Tantalum nitride films deposited by reactive sputtering in an rf magnetron sputtering system have been found to form excellent Schottky barriers on n-type Si with an effective barrier height of 0.74 eV and an ideality factor of <1.1. Following a postdeposition 500 °C anneal, the Au/Ti-W/ TaN/n-Si structures exhibit little degradation of electrical properties when sustained at that temperature. The current-voltage characteristics begin to degrade at 600 °C, and evaluation of the capacitance-voltage data of degraded devices shows a rapid rise in surface donor concentration at anneal temperatures above 600 °C, evidently caused by the penetration of Ta (a deep donor in Si) into Si.