Ultimate sized nano‐dots formed by electron beam‐induced deposition using an ultrahigh vacuum transmission electron microscope

Tanaka, Miyoko; Shimojo, Makoto; Han, Ming; Mitsuishi, Kazutaka; Furuya, Kazuo

doi:10.1002/sia.1978

Cited by 48 publications

(48 citation statements)

References 16 publications

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“…Stopping the growth process in its initial stage influences also the height of the deposits, so in this regime it is not possible to control the aspect ratio independently of the width of the deposit merely with the accumulated charge. Sub-10-nm structures have been fabricated with widths of 8, 75,76 5, 77 4, 78 3.5, 79 1.5, 80 and even 1.0 nm. 81 While for large deposits the deposited mass is identical every time the experiment is repeated, a significant variation in mass is found for the very smallest deposits.…”

Section: Widthmentioning

confidence: 99%

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: Widthmentioning

confidence: 99%

A critical literature review of focused electron beam induced deposition

Dorp

Hagen

2008

Journal of Applied Physics

486

577

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“…In this way, two-and three-dimensional nanoscale structures can be deposited at a resolution of Ϸ1.0 nm. 4,5 Current applications of FEBIP include photolithographic mask repair and the production of high aspect ratio scanning probe tips. [6][7][8][9][10][11][12][13][14] Future applications may include the fabrication of nanoelectronic components.…”

Section: Introductionmentioning

confidence: 99%

Atomic radical abatement of organic impurities from electron beam deposited metallic structures

Wnuk

Gorham

Rosenberg

et al. 2010

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

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Focused electron beam induced processing ͑FEBIP͒ of volatile organometallic precursors has become an effective and versatile method of fabricating metal-containing nanostructures. However, the electron stimulated decomposition process responsible for the growth of these nanostructures traps much of the organic content from the precursor's ligand architecture, resulting in deposits composed of metal atoms embedded in an organic matrix. To improve the metallic properties of FEBIP structures, the metal content must be improved. Toward this goal, the authors have studied the effect of atomic hydrogen ͑AH͒ and atomic oxygen ͑AO͒ on gold-containing deposits formed from the electron stimulated decomposition of the FEBIP precursor, dimethyl-͑acetylacetonate͒ gold͑III͒, Au III ͑acac͒Me 2 . The effect of AH and AO on nanometer thick gold-containing deposits was probed at room temperature using a combination of x-ray photoelectron spectroscopy ͑XPS͒, scanning Auger electron spectroscopy, and atomic force microscopy ͑AFM͒. XPS revealed that deposits formed by electron irradiation of Au III ͑acac͒Me 2 are only Ϸ10% gold, with Ϸ80% carbon and Ϸ10% oxygen. By exposing deposits to AH, all of the oxygen atoms and the majority of the carbon atoms were removed, ultimately producing a deposit composed of Ϸ75% gold and Ϸ25% carbon. In contrast, all of the carbon could be etched by exposing deposits to AO, although some gold atoms were also oxidized. However, oxygen was rapidly removed from these gold oxide species by subsequent exposure to AH, leaving behind purely metallic gold. AFM analysis revealed that during purification, removal of the organic contaminants was accompanied by a decrease in particle size, consistent with the idea that the radical treatment of the electron beam deposits produced close packed, gold particles. The results suggest that pure metallic structures can be formed by exposing metal-containing FEBIP deposits to a sequence of AO followed by AH.

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“…As the electron beam can be focused onto a region of one nanometer to several hundred nanometers using a modern electron microscope, a solid deposit is formed in the irradiated regions on the surface of the substrate. Schematic illustrations of the experimental setup for EBID are shown in figure 1 and the details of the experiments are given elsewhere [14][15][16][17][18][19]. For example, when the vapor of tungsten hexacarbonyl (W(CO) 6 )is used as a precursor gas, the electron irradiation decomposes the gas into W, CO, C, O and various molecular species.…”

Section: Experiments On Electron-beam-induced Depositionmentioning

confidence: 99%

“…We infer that there is a critical partial pressure for the dot fabrication, although it is possible that the nanodots were too small to be distinguished. Figure 22(a) shows an array of dots formed using a 1 nm probe and a deposition period of 5 s [16]. The dots are located at the intersections of the white lines, but it is difficult to distinguish them from the amorphous substrate.…”

Section: Resolution Limit In Ultrahigh Vacuummentioning

confidence: 99%

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Nanofabrication by advanced electron microscopy using intense and focused beam^∗

Furuya

2008

Science and Technology of Advanced Materials

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The nanogrowth and nanofabrication of solid substances using an intense and focused electron beam are reviewed in terms of the application of scanning and transmission electron microscopy (SEM, TEM and STEM) to control the size, position and structure of nanomaterials. The first example discussed is the growth of freestanding nanotrees on insulator substrates by TEM. The growth process of the nanotrees was observed in situ and analyzed by high-resolution TEM (HRTEM) and was mainly controlled by the intensity of the electron beam. The second example is position-and size-controlled nanofabrication by STEM using a focused electron beam. The diameters of the nanostructures grown ranged from 4 to 20 nm depending on the size of the electron beam. Magnetic nanostructures were also obtained using an iron-containing precursor gas, Fe(CO) 5 . The freestanding iron nanoantennas were examined by electron holography. The magnetic field was observed to leak from the nanostructure body which appeared to act as a 'nanomagnet'. The third example described is the effect of a vacuum on the size and growth process of fabricated nanodots containing W in an ultrahigh-vacuum field-emission TEM (UHV-FE-TEM). The size of the dots can be controlled by changing the dose of electrons and the partial pressure of the precursor. The smallest particle size obtained was about 1.5 nm in diameter, which is the smallest size reported using this method. Finally, the importance of a smaller probe and a higher electron-beam current with atomic resolution is emphasized and an attempt to develop an ultrahigh-vacuum spherical aberration corrected STEM (Cs-corrected STEM) at NIMS is reported.

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Ultimate sized nano‐dots formed by electron beam‐induced deposition using an ultrahigh vacuum transmission electron microscope

Cited by 48 publications

References 16 publications

A critical literature review of focused electron beam induced deposition

A critical literature review of focused electron beam induced deposition

Atomic radical abatement of organic impurities from electron beam deposited metallic structures

Nanofabrication by advanced electron microscopy using intense and focused beam^∗

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Ultimate sized nano‐dots formed by electron beam‐induced deposition using an ultrahigh vacuum transmission electron microscope

Cited by 48 publications

References 16 publications

A critical literature review of focused electron beam induced deposition

A critical literature review of focused electron beam induced deposition

Atomic radical abatement of organic impurities from electron beam deposited metallic structures

Nanofabrication by advanced electron microscopy using intense and focused beam∗

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Product

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Nanofabrication by advanced electron microscopy using intense and focused beam^∗