[20p-S221-1~17] 13.3 Insulator technology

▲ [20p-S221-6] Anomalous Flatband Voltage Shift of AlF_xO_y/Al₂O₃ MOS Capacitors: Dipole Layer Formation at Dielectric Interfaces with Different Anions

〇(D)Jiayang Fei¹, Koji Kita¹ (1.The Univ. of Tokyo)

Keywords:gate dielectric,dipole layer,flatband voltage shift

The dipole layer formed at high-k/SiO₂ has been recognized as a promising way to adjust the threshold voltage of MOSFETs. To reasonably explain the directions and magnitudes of dipoles for various high-k/SiO₂ systems, the anion (= oxygen ion) density difference at the interface has been pointed out to be the most important factor, even though the role of cation migration should be also taken into account for the cases of reactive systems. In this study we investigated the flatband voltage shift caused by an Al₂O₃/AlF_xO_y interface, due to the dipole layer formation at the dielectric interface of common cations but different anions (O^- and F^-), to clarify that the previous model can be extended to the multi-anion systems.