High-throughput direct writing of metallic micro- and nano-structures by focused Ga+beam irradiation of palladium acetate films

Metallic nanopatterns are ubiquitous in applications that exploit the electrical conduction at the nanoscale, including interconnects, electrical nanocontacts, and small gaps between metallic pads. These metallic nanopatterns can be designed to show additional physical properties (optical transparency, plasmonic effects, ferromagnetism, superconductivity, heat evacuation, etc.). For these reasons, an intense search for novel lithography methods using uncomplicated processes represents a key on-going issue in the achievement of metallic nanopatterns with high resolution and high throughput. In this contribution, we introduce a simple methodology for the efficient decomposition of Pd3(OAc)6 spin-coated thin films by means of a focused Ga+ beam, which results in metallic-enriched Pd nanostructures. Remarkably, the usage of a charge dose as low as 30 μC/cm2 is sufficient to fabricate structures with a metallic Pd content above 50% (at.) exhibiting low electrical resistivity (70 μΩ·cm). Binary-collision-approximation simulations provide theoretical support to this experimental finding. Such notable behavior is used to provide three proof-of-concept applications: (i) creation of electrical contacts to nanowires, (ii) fabrication of small (40 nm) gaps between large metallic contact pads, and (iii) fabrication of large-area metallic meshes. The impact across several fields of the direct decomposition of spin-coated organometallic films by focused ion beams is discussed.Authors acknowledge grants PID2019-105881RB-I00 and PID2020-112914RB-I00, MAT2017-82970-C2-2-R (including FEDER funding), funded by MCIN/AEI/10.13039/501100011033, CSIC, through projects PIE202060E187 and Research Platform PTI-001 and also Gobierno de Aragón through the grant number E13_20R and E31_20R with the European Social Fund (Construyendo Europa desde Aragón). P.P. is grateful to the National Research Fund (FNR), Luxembourg (C17/MS/11682850/ULOWBEAM). The following networking projects are acknowledged: Spanish Nanolito (RED2018-102627-T), COST-FIT4NANO (action CA19140), and OsMolsys (RED2018-102833-T). Technical support by the LMA technicians at Universidad de Zaragoza is acknowledged.Peer reviewe