Control of a metal-electrode work function by solid-state diffusion of nitrogen

R.J.P. Lander, J. C. Hooker, J. P. Van Zijl, F. Roozeboom, Martien P.M. Maas, Y. Tamminga, R.A.M. Wolters

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

2 Citations (Scopus)

Abstract

The work function of a metal gate electrode has been adjusted with the introduction of nitrogen by solid-source diffusion from an over-stoichiometric TiN1+x layer. RBS measurements have shown that measurable concentrations of nitrogen can be diffused into a 10nm Ta layer at moderate anneal temperatures (>500°C), and that this concentration increases with temperature in the range 500-1000°C. Capacitance-voltage measurements have been carried out on 1Onm tantalum layers on Al2O3. These measurements have indicated that the work function of tantalum changes by -0.08eV due to the presence of the over-stoichiometric TiN1+x covering layer during anneal (800°C/30 inch). Similar C-V measurements have been carried out on 10nm molybdenum layers on SiO2 and on Al2O3 dielectrics. These have shown that the work function of molybdenum is substantially different for metal stacks with the TiN1+x covering layer after a similar anneal. The work function changes by -0.52eV for molybdenum on SiO2 and by 1.1eV for molybdenum on Al2O3. The results suggest great potential for molybdenum as a candidate for a single-metal dual-work function approach to integrating metal gates into future CMOS technologies.

Original languageEnglish
Title of host publicationSilicon Materials - Processing, Characterization and Reliability
Place of PublicationWarrendale
PublisherMaterials Research Society
Pages253-258
Number of pages6
ISBN (Print)1-55899-652-4
Publication statusPublished - 1 Dec 2002
Externally publishedYes
EventSilicon Materials - Processing, Characterization and Reliability - San Francisco, CA, United States
Duration: 1 Apr 20025 Apr 2002

Publication series

NameMaterials Research Society Symposium - Proceedings
Volume716
ISSN (Print)0272-9172

Conference

ConferenceSilicon Materials - Processing, Characterization and Reliability
Country/TerritoryUnited States
CitySan Francisco, CA
Period1/04/025/04/02

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