ALD for 3D Nanofabrication

ALD for 3D Nanofabrication

Due to the self-limited nature of ALD chemical reactions, unprecedented thickness conformallity can be achieved over the most challenging 3D nanostructures. As a result, ALD has become the technique of choice to deposit a wide array of thin films to fill cavities and trenches, obtain nanowires and nanotubes, conformally coat high aspect ratio nanotemplates and high surface area nanoparticles. Today ALD is used in state-of-the-art applications ranging for all solid-state lithium ion batteries (LIB) to high surface area frameworks for water splitting. Below is a short selection of the many published examples of high quality nanostructures synthesized using ALD in Cambridge Nanotech ALD tools.

SEM cross-section of 3D cavity coated with conformal Al2O3 / TiO2 (ATO) nano-laminate ALD film. Courtesy of O. Poncelet, L. Francis, Univ. de Louvain – Deposited in Fiji® system.

Magnetic iron nanotube with SiO2 / Fe3O4 / SiO2 deposited in 10-30µm deep AAO nanotemplate. Aspect ratio 150 to 590 deposited in Savannah® with Expo mode using 3DMASi, FeCp2, ozone.Pitzschel, K. et al. ACS Nano 3, 3463–3468 (2009).

Fabrication of high surface area conducting and transparent frameworks for photo-oxidation of water with Fe2O3 / ITO / SiO2 ALD films deposited on inverse opal scaffoldRiha, S. C.. Acs Appl Mater Inter 5, 360–367 (2013).

Solid electrolyte Li5.1TaOz deposited by ALD in AAO structure. Deposited in Savannah® under expo mode with up to 470:1 aspect ratio.
Liu, J. et al., J. Phys. Chem. C 117, 20260–20267 (2013)

Electrochemically active LiFePO4 ALD film deposited on carbon nanotubes for lithium-ion battery cathode. Deposited in Savannah® system under expo mode at 300˚C.
Liu, J. et al. Adv. Mat. (2014).

Quaternary Cu2ZnSnS4 deposited by ALD in silicon trench. CZST is a potential low cost semiconductor for photovoltaic application. Deposited in Savannah® under expo mode with H2S kit.
Thimsen, E. et al. Chem Mater 24, 3188–3196 (2012).

Ultrathin FePO4 as an electrochemically active barrier on LMNO particles to prevent electrolyte oxidation. Deposited in Savannah® under expo mode.
Xiao, B. et al. Adv. Sci. (2015).

TiO2 in AAO templates and TiO2 nanotubes for Dye Sensitized Solar Cell (DSSC)
Gao, X. J Power Sources (2013).

TiO2-ZnO coresheath composite structure for enhanced DSSC. The 1.3nm thick ZnO layer is deposited by ALD in a Fiji® F200 system.
Ulusoy, T. G., J. Mater. Chem. A2, 16867–16876 (2014).

Sequential Infiltration Synthesis (SIS) for nanopatterning high aspect ratio metal oxide structures. AlOx infiltration done SU8 in Savannah® at 95˚C.
Nam, C.-Y. J Vac Sci Technol B 33, 06F201–8 (2015).

AlN on nylon 6,6 nanofibres deposited in Fiji® ALD system.
Haider, A. et al. APL Mater. 2, 096109–9 (2014).

Platinum nanotube array electrode after removal of AAO template. Pt deposited by ALD in Fiji® F200.
Galbiati, S. Electrochimica Acta 125, 107–116 (2014).

Monocrystalline ZnAl2O4 spinel nanotubes deposited in Savannah® under expo mode.
Jin fan, Nature Materials 5, 627–631 (2006).

ZnO-Al2O3 coreshell nanowires synthesized in Fiji® ALD system.
Thomas, J Vac Sci Technol A 30, (2012).

Single cell Photonic nanocavity probe with Al2O3/ZrO2 nanolaminate to prevent oxidation
Shambat, G. et al. Single-cell Photonic Nanocavity Probes. Nano Lett 130206113907001 (2013).