title: Versatile Fabrication of Self-Aligned Nanoscale Hall Devices Using Nanowire Masks.
abstract: In this work, we present an ingenious method to fabricate self-aligned nanoscale Hall devices using chemically synthesized nanowires as both etching and deposition masks. This versatile method can be extensively used to make nanoribbons out of arbitrary thin films without the need for extremely high alignment accuracy to define the metal contacts. The fabricated nanoribbon width scales with the mask nanowire width (diameter), and it can be easily reduced down to tens of nanometers. The self-aligned metal contacts from the sidewall extend to the top surface of the nanoribbon, and the overlap can be controlled by tuning the deposition recipe. To demonstrate the feasibility, we have fabricated Ta/CoFeB/MgO nanoribbons sputtered on a SiO2/Si substrate with different metal contacts, using synthesized SnO2 nanowires as masks. Anomalous Hall effect measurements have been carried out on the fabricated nanoscale Hall device in order to study the current-induced magnetization switching in the nanoscale heavy metal/ferromagnet heterostructure, which has shown distinct switching behaviors from micron-scale devices. The developed method provides a useful fabrication platform to probe the charge and spin transport in the nanoscale regime.
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Jianshi
authors.initials: J
authors.lastname: Tang
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Yu
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University of Science and Technology , Taipei City, Taiwan 10607, Republic of China.
authors.forename: Chiu-Yen
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Li-Te
authors.initials: LT
authors.lastname: Chang
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Wanjun
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Congli
authors.initials: C
authors.lastname: He
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Kang L
authors.initials: KL
authors.lastname: Wang
keywords: Hall effect; Nanowire; current-induced magnetization switching; nanoribbon; self-aligned contacts