Influence of secondary electrons in proximal probe lithography

Völkel, B.; Gölzhäuser, Armin; Müller, H. U.; Dávid, Christian; Grunze, M.

doi:10.1116/1.589748

Cited by 49 publications

(43 citation statements)

References 8 publications

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“…19͑a͔͒. 95 The most significant change is in the total yield of emitted electrons, which increases sharply to a maximum with increasing PE energy, after which it slowly decreases ͓see Fig. 19͑b͔͒.…”

Section: B Electron Energymentioning

confidence: 98%

A critical literature review of focused electron beam induced deposition

Dorp

Hagen

2008

Journal of Applied Physics

486

577

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An extensive review is given of the results from literature on electron beam induced deposition. Electron beam induced deposition is a complex process, where many and often mutually dependent factors are involved. The process has been studied by many over many years in many different experimental setups, so it is not surprising that there is a great variety of experimental results. To come to a better understanding of the process, it is important to see to which extent the experimental results are consistent with each other and with the existing model. All results from literature were categorized by sorting the data according to the specific parameter that was varied ͑current density, acceleration voltage, scan patterns, etc.͒. Each of these parameters can have an effect on the final deposit properties, such as the physical dimensions, the composition, the morphology, or the conductivity. For each parameter-property combination, the available data are discussed and ͑as far as possible͒ interpreted. By combining models for electron scattering in a solid, two different growth regimes, and electron beam induced heating, the majority of the experimental results were explained qualitatively. This indicates that the physical processes are well understood, although quantitatively speaking the models can still be improved. The review makes clear that several major issues remain. One issue encountered when interpreting results from literature is the lack of data. Often, important parameters ͑such as the local precursor pressure͒ are not reported, which can complicate interpretation of the results. Another issue is the fact that the cross section for electron induced dissociation is unknown. In a number of cases, a correlation between the vertical growth rate and the secondary electron yield was found, which suggests that the secondary electrons dominate the dissociation rather than the primary electrons. Conclusive evidence for this hypothesis has not been found. Finally, there is a limited understanding of the mechanism of electron induced precursor dissociation. In many cases, the deposit composition is not directly dependent on the stoichiometric composition of the precursor and the electron induced decomposition paths can be very different from those expected from calculations or thermal decomposition. The dissociation mechanism is one of the key factors determining the purity of the deposits and a better understanding of this process will help develop electron beam induced deposition into a viable nanofabrication technique.

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Section: B Electron Energymentioning

confidence: 98%

A critical literature review of focused electron beam induced deposition

Dorp

Hagen

2008

Journal of Applied Physics

486

577

View full text Add to dashboard Cite

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“…Proximity effects in e-beam lithography such as backscattered electrons 6 are absent in HDL. Since HDL is typically performed below 10 V, secondary electron production and backscattering are minimized, eliminating these e-beam lithography proximity effects, although backscattered electron effects have been observed for HDL above 20 V. 7,8 However, the presence of the tip does introduce an additional proximity effect in HDL not typically seen in e-beam lithography: production of DBs due to the presence of hydrogen atoms nominally liberated from the surface. This is a resist-induced proximity effect.…”

Section: Introductionmentioning

confidence: 98%

Spurious dangling bond formation during atomically precise hydrogen depassivation lithography on Si(100): The role of liberated hydrogen

Ballard¹,

Owen²,

Alexander³

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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The production of spurious dangling bonds during the hydrogen depassivation lithography process on Si(100)-H is studied. It is shown that the number of spurious dangling bonds produced depends on the size of the primary pattern on the surface, not on the electron dose, indicating that the spurious dangling bonds are formed via an interaction of the liberated hydrogen with the surface. It is also shown that repassivation may occur if hydrogen depassivation lithography is performed near an already patterned area. Finally, it is argued that the product of the interaction is a single dangling bond next to a monohydride silicon on a silicon dimer, with a reaction probability much in excess of that previously observed.

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“…Firstly, the secondary electron yield for 35 keV He + ions impinging perpendicularly on a Au substrate is calculated by the software package IONiSE to be about 2.7 [26]. And this is approximately three times higher than the experimentally determined secondary electron yield (approximately 0.85) for 100 eV electrons [27]. Secondly, the energy spectrum of secondary electrons excited by 35 keV He + ions on Au showed a peak around 2 eV, with a small shoulder in the range of 5–6 eV [28].…”

Section: Resultsmentioning

confidence: 99%

Fabrication of carbon nanomembranes by helium ion beam lithography

Zhang¹,

Vieker²,

Beyer³

et al. 2014

Beilstein J. Nanotechnol.

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SummaryThe irradiation-induced cross-linking of aromatic self-assembled monolayers (SAMs) is a universal method for the fabrication of ultrathin carbon nanomembranes (CNMs). Here we demonstrate the cross-linking of aromatic SAMs due to exposure to helium ions. The distinction of cross-linked from non-cross-linked regions in the SAM was facilitated by transferring the irradiated SAM to a new substrate, which allowed for an ex situ observation of the cross-linking process by helium ion microscopy (HIM). In this way, three growth regimes of cross-linked areas were identified: formation of nuclei, one-dimensional (1D) and two-dimensional (2D) growth. The evaluation of the corresponding HIM images revealed the dose-dependent coverage, i.e., the relative monolayer area, whose density of cross-links surpassed a certain threshold value, as a function of the exposure dose. A complete cross-linking of aromatic SAMs by He+ ion irradiation requires an exposure dose of about 850 µC/cm2, which is roughly 60 times smaller than the corresponding electron irradiation dose. Most likely, this is due to the energy distribution of secondary electrons shifted to lower energies, which results in a more efficient dissociative electron attachment (DEA) process.

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Influence of secondary electrons in proximal probe lithography

Cited by 49 publications

References 8 publications

A critical literature review of focused electron beam induced deposition

A critical literature review of focused electron beam induced deposition

Spurious dangling bond formation during atomically precise hydrogen depassivation lithography on Si(100): The role of liberated hydrogen

Fabrication of carbon nanomembranes by helium ion beam lithography

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