Expanding 3D Nanoprinting Performance by Blurring the Electron Beam

Abstract

Additive, direct-write manufacturing via a focused electron beam has evolved into a reliable 3D nanoprinting technology in recent years. Aside from low demands on substrate materials and surface morphologies, this technology allows the fabrication of freestanding, 3D architectures with feature sizes down to the sub-20 nm range. While indispensably needed for some concepts (e.g., 3D nano-plasmonics), the final applications can also be limited due to low mechanical rigidity, and thermal- or electric conductivities. To optimize these properties, without changing the overall 3D architecture, a controlled method for tuning individual branch diameters is desirable. Following this motivation, here, we introduce on-purpose beam blurring for controlled upward scaling and study the behavior at different inclination angles. The study reveals a massive boost in growth efficiencies up to a factor of five and the strong delay of unwanted proximal growth. In doing so, this work expands the design flexibility of this technology.

Expanding FEBID-Based 3D-Nanoprinting toward Closed High-Fidelity Nanoarchitectures

“…All experiments used a Pt-based precursor under working conditions of a primary beam energy E 0 = 5 keV, a beam current I 0 = 40 pA, and an in-plane point pitch (pixel-to-pixel distance) of PoP = 25 nm, which corresponds to ∼25% beam profile overlap according to the microscope specifications under the chosen focusing conditions. The main motivation for selecting a 5 keV beam energy lies in the fact that low primary energies have fewer implications for 3D elements underneath the actually grown segments due to reduced transmission contributions. , Additionally, lower E 0 values are also beneficial with respect to the angle-dependent cross-sectional shape conservation compared to high primary electron energies. , More details relating to the specific choice of PoPs and DTs can be found in Supplement 1. As the patterns can be considered as a side-by-side deposition of small single pillars, the wall thickness is very similar to the diameter of a single pillar, which is about 100 nm for our conditions.…”

“…The main motivation for selecting a 5 keV beam energy lies in the fact that low primary energies have fewer implications for 3D elements underneath the actually grown segments due to reduced transmission contributions. 9,26 Additionally, lower E 0 values are also beneficial with respect to the angle-dependent cross-sectional shape conservation compared to high primary electron energies. 10,26 More details relating to the specific choice of PoPs and DTs can be found in Supplement 1.…”

FEBID 3D-Nanoprinting at Low Substrate Temperatures: Pushing the Speed While Keeping the Quality

“…To avoid such unwanted growth variations along the wire length, one can apply different counter measures: (1) reducing the beam current (at the cost of volume growth rates) [3], (2) increasing the primary beam energy for less inelastic scattering events (at the cost of more circular wire cross-sectional shapes [3]), (3) introducing additional refresh times between subsequent patterning pulses [14] (at the cost of process time, or interlacing for multi-branch structures [13]) or (4) introducing a beam blur (reducing electron density and thermal resistance at the cost of minimal feature size [28]). Another approach to reduce beam induced heating effects and to increase deposition speeds at the same time is cooling the substrate.…”

Editorial for the Special Issue on Nanofabrication with Focused Electron/Ion Beam Induced Processing

“…Accordingly, this Special Issue showcases seven research articles and one review article that focus on the current status of nanofabrication using focused electron/ion beam induced processing. These articles particularly explore the following aspects of these technologies: (1) purification of FEBID nanostructures [ 1 ], (2) high-resolution nanostructures using FEBID [ 2 ], (3) a new approach for the nanofabrication of metallic nanostructures based on FEB [ 3 ], (4) tuning of diameters in 3D FEBID nanostructures [ 4 ], (5) evolution of the microstructure and resistivity in Pt Ga + FIBID deposits with in situ heating [ 5 ], (6) nanofabrication using Ga + FIB-induced processing for photonic applications [ 6 ], and (7) fabrication of 3D FIBID nanostructures using He + FIB [ 7 , 8 ].…”

“…(4) Tuning of diameters in 3D FEBID nanostructures: Lukas Seewald et al [ 4 ] have optimized a method for tuning diameters of individual 3D nanowires. In particular, authors have introduced beam blurring for controlled upward scaling and study the behavior at different inclination angles.…”