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 language | English (US) |
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Pages (from-to) | 102111 |
Journal | Applied Physics Letters |
Volume | 100 |
Issue number | 10 |
DOIs | |
State | Published - Mar 10 2012 |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)