Variable work function in MOS capacitors utilizing nitrogen-controlled TiNx gate electrodes
2004 (English)In: Microelectronic Engineering, ISSN 0167-9317, Vol. 75, no 4, 389-396 p.Article in journal (Refereed) Published
A substantial shift in the work function of TiNx by as much as 0.7 eV is achieved by varying the nitrogen gas flow during the reactive sputter deposition of the metal gate, which indicates tunability for replacing poly-Si in a CMOS process. TiNx MOS capacitors having multiple SiO2 thicknesses have been evaluated and the work function of TiNx can be altered from 4.2 to 4.9 eV depending on the nitrogen content. The values are stable after RTP annealing up to 600 °C in nitrogen gas for 30 s, although annealing at 800 °C changes the work function for the different compositions towards a mid-gap value. No variation in EOT with annealing temperature is observed for the TiNx/SiO2 stacks deposited at high nitrogen gas flow. The change in work function appears not to be correlated to the crystalline orientation of the TiNx. The work function is instead believed to be affected by extrinsic states in the metal/dielectric interface.
Place, publisher, year, edition, pages
2004. Vol. 75, no 4, 389-396 p.
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:uu:diva-94803DOI: 10.1016/j.mee.2004.07.061OAI: oai:DiVA.org:uu-94803DiVA: diva2:168790