title: Correlation between Al grain size, grain boundary grooves and local variations in oxide barrier thickness of Al/AlOx/Al tunnel junctions by transmission electron microscopy.
abstract: A thickness variation of only one Ångström makes a significant difference in the current through a tunnel junction due to the exponential thickness dependence of the current. It is thus important to achieve a uniform thickness along the barrier to enhance, for example, the sensitivity and speed of single electron transistors based on the tunnel junctions. Here, we have observed that grooves at Al grain boundaries are associated with a local increase of tunnel barrier thickness. The uniformity of the barrier thickness along the tunnel junction thus increases with increasing Al grain size. We have studied the effect of oxidation time, partial oxygen pressure and also temperature during film growth on the grain size. The implications are that the uniformity improves with higher temperature during film growth.
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Samira
authors.initials: S
authors.lastname: Nik
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Philip
authors.identifier: 0000-0002-8553-3353
authors.initials: P
authors.lastname: Krantz
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Lunjie
authors.initials: L
authors.lastname: Zeng
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Tine
authors.initials: T
authors.lastname: Greibe
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Pettersson
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Gustafsson
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Delsing
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Olsson
keywords: Grain size; TEM; Tunnel junction