[15a-B9-1~6] 13.3 Insulator technology

▼ [15a-B9-6] Consideration on the Origin of Dipole Layer Formation at Dielectric Interfaces with Different Anions (Fluorine, Oxygen and Nitrogen)

〇(D)Jiayang Fei¹, Ryota Kunugi², Takanobu Watanabe², Koji Kita¹ (1.The Univ. of Tokyo, 2.Waseda Univ.)

Keywords:dipole layer, flatband voltage shift, gate dielectric

Oxygen density difference has been widely accepted as the origin of diople layer formation at high-k/SiO₂ interface which can be employed to shift the flatband votlage (V_fb) of MOS capacitors. To gain a further understanding of the origin of dipole layer formation at general dielectric interfaces, we investigated possible dipole layer formation at AlF_xO_y/Al₂O₃ interface by studying the V_fb shift of this interface, which showed a AlF_xO_y (-)/Al₂O₃ (+) dipole layer formation and was reported previously. In this study, we further clarfify the driving force by calculating the displacements of all atoms at interface after molecular dynamic simulation of AlF₃/Al₂O₃. Furthermore, we have performed experiments on other dielectric systems with different anions (AlN_xO_y/Al₂O₃ and AlN_xO_y/AlF_xO_y) to investigate other possible factors that could affect the dipole layer formation in addition to the anion density difference.