Anomalous positive flatband voltage shifts in metal gate stacks containing rare-earth oxide capping layers
AuthorsCaraveo-Frescas, Jesus Alfonso
Hedhili, Mohamed N.
Alshareef, Husam N.
KAUST DepartmentAdvanced Nanofabrication, Imaging and Characterization Core Lab
Imaging and Characterization Core Lab
Materials Science and Engineering Program
Physical Sciences and Engineering (PSE) Division
Permanent link to this recordhttp://hdl.handle.net/10754/552880
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AbstractIt 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.
CitationAnomalous positive flatband voltage shifts in metal gate stacks containing rare-earth oxide capping layers 2012, 100 (10):102111 Applied Physics Letters
JournalApplied Physics Letters