title: Contacting ZnO Individual Crystal Facets by Direct Write Lithography.
abstract: Many advanced electronic devices take advantage of properties developed at the surface facets of grown crystals with submicrometer dimensions. Electrical contacts to individual crystal facets can make possible the investigations of facet-dependent properties such as piezoelectricity in ZnO or III-nitride crystals having noncentrosymmetric structure. However, a lithography-based method for developing contacts to individual crystal facets with submicrometer size has not yet been demonstrated. In this report we study the use of electron beam-induced deposition (EBID), a direct write lithography method, for contacting individual facets of ZnO pillars within an electron microscope. Correlating structural and in situ deposition and electrical data, we examine proximity effects during the EBID and evaluate the process against obtaining electrically insulated contact lines on neighboring and diametrically opposite ZnO facets. Parameters such as incident beam energy geometry and size of the facets were investigated with the view of minimizing unwanted proximity broadening effects. Additionally, we show that the EBID direct write method has the required flexibility, resolution, and minimized proximity deposition for creating prototype devices. The devices were used to observe facet-dependent effects induced by mechanical stress on single ZnO pillar structures.
authors.affiliation: Tyndall National Institute, Lee Maltings and Cork Institute of Technology , Rosa Avenue, Cork, Ireland.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Petkov
authors.affiliation: MTA EK Institute of Technical Physics and Materials Science , Konkoly Thege M. út 29-33, 1121 Budapest, Hungary.
authors.forename: János
authors.initials: J
authors.lastname: Volk
authors.affiliation: MTA EK Institute of Technical Physics and Materials Science , Konkoly Thege M. út 29-33, 1121 Budapest, Hungary.
authors.forename: Róbert
authors.initials: R
authors.lastname: Erdélyi
authors.affiliation: MTA EK Institute of Technical Physics and Materials Science , Konkoly Thege M. út 29-33, 1121 Budapest, Hungary.
authors.forename: István Endre
authors.initials: IE
authors.lastname: Lukács
authors.affiliation: International Center for Materials Nanoarchitectonics, National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nagata
authors.affiliation: Universität Leipzig , Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany.
authors.forename: Chris
authors.initials: C
authors.lastname: Sturm
authors.affiliation: Universität Leipzig , Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Grundmann
keywords: ZnO pillars; electron beam-induced deposition; facet-dependent; in situ electrical testing; piezoelectric sensors; proximity deposition