An interface dipole model explaining threshold voltage (Vt) tuning in HfSiON gated n -channel field effect transistors (nFETs) is proposed. Vt tuning depends on rare earth (RE) type and diffusion in SiSi Ox HfSiON REOx /metal gated nFETs as follows: Sr<Er<Sc+Er<La<Sc<none. This Vt ordering is very similar to the trends in dopant electronegativity (EN) (dipole charge transfer) and ionic radius (r) (dipole separation) expected for a interfacial dipole mechanism. The resulting Vt dependence on RE dopant allows distinction between a dipole model (dependent on EN and r) and an oxygen vacancy model (dependent on valence).
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)