title: A study of threshold switching of NbO2 using atom probe tomography and transmission electron microscopy.
abstract: Threshold switching is a phenomenon where the resistivity of an insulating material changes and the insulator exhibits metallic behavior. This could be explained by phase transformation in oxide materials; however, this behavior is also seen in amorphous insulators. In this study, through an ex-situ experiment using transmission electron microscopy (TEM), we proved that threshold switching of amorphous NbO2 accompanies local crystallization. The change in I-V characteristics after electroforming was examined by evaluating the concentration profile. Atom probe tomography (APT) combined with in-situ TEM probing technique was performed to understand the threshold switching in amorphous NbO2. The local crystallization in amorphous NbO2 was validated by the observed difference in time-of-flight (ToF) between amorphous and crystalline NbO2. We concluded that the slower ToF of amorphous NbO2 (a-NbO2) compared with crystalline NbO2 (c-NbO2) is due to the resistivity difference and trap-assisted recombination.
authors.affiliation: Semiconductor Business, Samsung Electronics, Hwasung 445-701, Republic of Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering (MSE), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: E J
authors.initials: EJ
authors.lastname: Cha
authors.affiliation: Department of Materials Science and Engineering (MSE), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: Y T
authors.initials: YT
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering (MSE), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: B K
authors.initials: BK
authors.lastname: Chae
authors.affiliation: Semiconductor Business, Samsung Electronics, Hwasung 445-701, Republic of Korea.
authors.forename: J J
authors.initials: JJ
authors.lastname: Kim
authors.affiliation: Semiconductor Business, Samsung Electronics, Hwasung 445-701, Republic of Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering (MSE), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Hwang
authors.affiliation: Department of Materials Science and Engineering (MSE), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea; National Center for Nanomaterials Technology (NCNT), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea. Electronic address: cgpark@postech.ac.kr.
authors.forename: C G
authors.initials: CG
authors.lastname: Park
keywords: Atom probe; Local crystallization; NbO(2); Threshold switching; Voltage drop