Determination of optical constant and electrical properties of sputtering-derived HfTiON gate dielectrics.

Nitrogen content dependent optical constant and electrical properties of sputtering-derived HfTiON gate dielectrics on Si substrate have been investigated. By means of characterization of ultraviolet–visible spectroscopy, reduction in band gap of HfTiON film has been detected with the increase in nitrogen concentration. Electrical measurements of MOS capacitor based on Al/HfTiON/Si gate stacks have indicated that a low interface-state density with almost ignorable frequency dispersion at applied gate voltage of 1 V have been obtained for all samples. With increasing the nitrogen concentration, the improved electrical performance has been observed. For the sample with Ar/N 2 flow ratio of 20/5, rapid thermal annealing (RTA) treatment at 200 °C achieves relatively favorable excellent electrical properties in terms of low gate leakage current density and oxide charge density ( Q ox ). The conduction mechanism for 200 °C-annealed sample has been analyzed systematically. [ABSTRACT FROM AUTHOR]