Anomalous positive flatband voltage shifts in metal gate stacks containing rare-earth oxide capping layers

Jesus Alfonso Caraveo-Frescas, Mohamed N. Hedhili, H. Wang, Udo Schwingenschlögl, Husam N. Alshareef

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

It is shown that the well-known negative flatband voltage (VFB) shift, induced by rare-earth oxide capping in metal gate stacks, can be completely reversed in the absence of the silicon overlayer. Using TaN metal gates and Gd2O3-doped dielectric, we measure a ∼350 mV negative shift with the Si overlayer present and a ∼110 mV positive shift with the Si overlayer removed. This effect is correlated to a positive change in the average electrostatic potential at the TaN/dielectric interface which originates from an interfacial dipole. The dipole is created by the replacement of interfacial oxygen atoms in the HfO2 lattice with nitrogen atoms from TaN.
Original languageEnglish (US)
Pages (from-to)102111
JournalApplied Physics Letters
Volume100
Issue number10
DOIs
StatePublished - Mar 10 2012

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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