Electrical and reliability characteristics of ultrathin oxynitride gate dielectric prepared by rapid thermal processing in N/sub 2/O

摘要

The electrical and physical characteristics of oxynitride grown in N/sub 2/O gas ambient have been studied. The dielectric growth rate in N/sub 2/O was found to be highly controllable and lower than that in O/sub 2/. Auger electron spectroscopy studies of oxynitride show a nitrogen-rich layer near the Si-SiO/sub 2/ interface. Compared with the control oxide, the oxynitride shows excellent electrical characteristics such as excellent diffusion barrier to dopant (BF/sub 2/), a significant reduction in interface state generation, less electron trapping, and much larger charge-to-breakdown under Fowler-Nordheim stress. A significantly lower threshold voltage shift and degradation of subthreshold swing under hot electron stress were also observed. These improvements can be explained by the nitrogen incorporation at Si-SiO/sub 2/ interface. This new oxynitride shows good promise for future ULSI application.