Electron-beam-induced deposition (EBID), also referred to as focused electron-beam-induced processing (FEBIP), is a lowvacuum materials processing technique in which a focused electron beam is used to directly write nanometer-sized structures onto a substrate in a constant partial pressure of precursor molecules. 1À4 EBID has a unique and attractive combination of capabilities, including high spatial resolution and the flexibility to deposit self-supporting three-dimensional nanostructures on nonplanar surfaces. EBID offers a number of advantages compared to other vacuum-based nanofabrication strategies. EBID is capable of creating smaller features than ion-beaminduced deposition (IBID), with less amorphization and without ion implantation. 5À7 Although the resolution of EBID is comparable to that of electron beam lithography (EBL) and extreme ultraviolet lithography (EUVL), 8,9 it needs no resist layers or etching step for pattern transfer. The advantages of EBID have also been recently been combined with those of atomic layer deposition (ALD) to create purely metallic but geometrically well-defined nanostructures. 10 Current applications of EBID include repairing masks used in UV lithography, 11À14 creating line gratings on vertical cavity surface emitting lasers, 15 and fabricating tips for scanning probe microscopy. 16,17

Using three different precursors [MeCpPtMe 3 , Pt(PF 3 ) 4 , and W(CO) 6 ], an ultra-high vacuum surface science approach has been used to identify and rationalize the effects of substrate temperature and electron fluence on the chemical composition and bonding in films created by electron beam induced deposition (EBID). X-ray photoelectron spectroscopy data indicate that the influence of these two processing variables on film properties is determined by the decomposition mechanism of the precursor. For precursors such as MeCpPtMe 3 that decompose during EBID without forming a stable intermediate, the film's chemical composition is independent of substrate temperature or electron fluence. In contrast, for Pt(PF 3 ) 4 and W(CO) 6 , the initial electron stimulated deposition event in EBID creates surface bound intermediates Pt(PF 3 ) 3 and partially decarbonylated W x (CO) y species, respectively. These intermediates can react subsequently by either thermal or electron stimulated processes. Consequently, the chemical composition of EBID films created from either Pt(PF 3 ) 4 or W(CO) 6 is influenced by both the substrate temperature and the electron fluence. Higher substrate temperatures promote the ejection of intact PF 3 and CO ligands from Pt(PF 3 ) 3 and W x (CO) y intermediates, respectively, improving the film's metal content. However, reactions of Pt(PF 3 ) 3 and W x (CO) y intermediates with electrons involve ligand decomposition, increasing the irreversibly bound phosphorous content in films created from Pt(PF 3 ) 4 and the degree of tungsten oxidation in films created from W(CO) 6 . Independent of temperature effects on chemical composition, elevated substrate temperatures (>25 C) increased the degree of metallic character within EBID deposits created from MeCpPtMe 3 and Pt(PF 3 ) 4 .

A retarding field energy analyzer (RFEA) with grids created by laser-cutting a honeycomb mesh in a 50 μm thick molybdenum foil is presented. The flat grids span an area of 1 cm and have high transmission (20 μm wide walls between 150 μm wide meshes). The molybdenum grids were tested in a 3-grid RFEA configuration with an analyzer depth of 0.87 mm.

We investigated chemical sputtering of silicon films by H y þ ions (with y being 2 and 3) in an asymmetric VHF Plasma Enhanced Chemical Vapor Deposition (PECVD) discharge in detail. In experiments with discharges created with pure H 2 inlet flows, we observed that more Si was etched from the powered than from the grounded electrode, and this resulted in a net deposition on the grounded electrode. With experimental input data from a power density series of discharges with pure H 2 inlet flows, we were able to model this process with a chemical sputtering mechanism. The obtained chemical sputtering yields were (0.3-0.4) 6 0

We present PECVD deposition of i‐a‐Si:H in an in‐line configuration for the fabrication of silicon heterojunction solar cells. For industry, in‐line processing has the potential to increase production throughput and yield. We compared batch and in‐line fabrication of i‐a‐Si:H passivation samples with identical plasma conditions and observed that the a‐Si:H material properties do not significantly differ. In batch‐type production the substrate is in the plasma zone at the moment of ignition, whereas for in‐line deposition the substrate is introduced into the plasma zone when steady plasma conditions have been reached. Our preliminary results show that there are depositions conditions that result both for in‐line and batch‐type deposition in good i‐a‐Si:H passivation layers. Therefore both methods can equally well be considered for the production of silicon heterojunction solar cells. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

We have critically evaluated the deposition parameter space of very high frequency plasma-enhanced chemical vapour deposition discharges near the amorphous to crystalline transition for intrinsic a-Si:H passivation layers on Si (1 1 1) wafers. Using a low silane concentration in the SiH4–H2 feedstock gas mixture that created amorphous material just before the transition, we have obtained samples with excellent surface passivation. Also, an a-Si:H matrix was grown with embedded local epitaxial growth of crystalline cones on a Si (1 1 1) substrate, as was revealed with a combined scanning electron and high-resolution transmission electron microscopy study. This local epitaxial growth was introduced by a decrease of the silane concentration in the feedstock gas or an increase in discharge power at low silane concentration. Together with the samples on Si (1 1 1) substrates, layers were co-deposited on Si (1 0 0) substrates. This resulted in void-rich, mono-crystalline epitaxial layers on Si (1 0 0). The epitaxial growth on Si (1 0 0) was compared to the local epitaxial growth on Si (1 1 1). The sparse surface coverage of cones seeded on the Si (1 1 1) substrate is most probably enabled by a combination of nucleation at steps and kinks in the {1 1 1} surface and intense ion bombardment at low silane concentration. The effective carrier lifetime of this sample is low and does not increase upon post-deposition annealing. Thus, sparse local epitaxial growth on Si (1 1 1) is enough to obstruct crystalline silicon surface passivation by amorphous silicon.

We studied ion bombardment during amorphous silicon layer deposition for hydrogen dilutions 5 to 59 with mass resolved IED measurements and simulations. The trends in the peak position of H 2 þ and SiH y þ IEDs with increasing hydrogen dilution show good agreement between measurements and simulations. A difference in asymmetry of the discharge between simulations and measurements results in a roughly 6 eV lower peak position for the simulations. An increasing SiH y þ ion flux with increasing hydrogen dilution is measured. We hypothesize that this is due to amorphous silicon etching that is enhanced by H y þ ion bombardment.

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