Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2008 May 27;9(1):014110.
doi: 10.1088/1468-6996/9/1/014110. eCollection 2008 Jan.

Nanofabrication by Advanced Electron Microscopy Using Intense and Focused Beam

Affiliations
Free PMC article
Review

Nanofabrication by Advanced Electron Microscopy Using Intense and Focused Beam

Kazuo Furuya. Sci Technol Adv Mater. .
Free PMC article

Abstract

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.

Keywords: Cs corrector; electron holography; electron-beam-induced deposition; iron carbonyl; nanorod; scanning transmission electron microscopy; ultrahigh vacuum.

Figures

Figure 1
Figure 1
Schematic drawings of EBID setup for (a) insulator and (b) electrically conductive substrates.
Figure 2
Figure 2
Nanostructures grown on Al2O3 substrate by EBID at room temperature: (a) and (b) at a current density of about 0.75 A cm−2, (c) at a current density of 12.9 A cm−2 and (d) at a current density of 33.0 A cm−2 nanodendrites (reproduced with permission from J. Phys. Conf. Ser. © 2008, IOP Publishing, Ltd).
Figure 3
Figure 3
(a) Nanodendrites grown on SiO2 substrate with an electron-beam accelerating voltage of 400 kV and a fluence of 6.0×1021 e cm−2, (b) enlarged image of frame in (a) and (c) EDS spectrum obtained from nanodendrites (reproduced with permission from Physica E 29 (2005) 564, © 2005, Elsevier, Ltd).
Figure 4
Figure 4
(a) Bright-field TEM image of as-fabricated Au nanoparticle/W nanodendrite compound structure on a SiO2 substrate and (b) EDS spectrum taken from a tip of the compound nanostructure. The W nanodendrites were fabricated with an electron beam irradiation fluence of 4.4 × 1021cm−2. Au nanoparticles were deposited using a rapid auto-coater system (JEOL JFC-1500). The anodic voltage used during sputtering was 1 kV and the anodic current was 7 mA. The ion-sputtering time was 7 s. The average Au nanoparticle size was measured to be 2.1 nm (reproduced with permission from Appl. Phys. Lett. 88 (2006) 263120–1, © 2006, American Institute of Physics).
Figure 5
Figure 5
Schematic diagram of the fabrication process involving selective deposition into ordered nanohole arrays of an anodic porous alumina membrane by EBID: (a) porous alumina after second anodization; (b) removal of Al layer; (c) the selective deposition by EBID and (d) ordered nanoparticle array in the holes of anodic porous alumina membrane.
Figure 6
Figure 6
TEM micrograph of anodic porous alumina membrane after EBID for 1 min (reproduced with permission from Appl. Surf. Sci. 241 (2005) 91, © 2005, Elsevier, Ltd).
Figure 7
Figure 7
EDS spectra taken from the deposition area: (a) from a hole and (b) from the matrix between the holes (reproduced with permission from Appl. Surf. Sci. 241 (2005) 91, © 2005, Elsevier, Ltd).
Figure 8
Figure 8
(a) Microdiffraction pattern taken from as-deposited nanoparticle in a hole. The electron-beam size in bright-field mode was about 30 nm in diameter, (b) corresponding HRTEM micrograph of a nanoparticle in the hole (reproduced with permission from Appl. Surf. Sci. 241 (2005) 91, © 2005, Elsevier, Ltd).
Figure 9
Figure 9
(a) Bright-field and (b) HAADF-STEM images of an array of dots deposited on a Si substrate using an FE-TEM (reproduced with permission from J. Vac. Sci. Technol. B 22 (2004) 742, © 2004, AVS The Science and Technology Society).
Figure 10
Figure 10
(a) Array of dots fabricated with different deposition times increasing from 1 ms at the upper left to 2.5 s at the lower right. (b) HRTEM image of a nanodot in (a). In the figure, the lattice fringes of Si are also seen. The diameter of the dot is 3.5 nm (reproduced with permission from Appl. Phys. Lett. 83 (2003) 2064, © 2003, American Institute of Physics).
Figure 11
Figure 11
Relation between deposition time and nanodot size. The dot size was measured using the FWHM to exclude the effect of image contrast; (circles) observed by HAADF-STEM and (squares) and (diamonds) deposited at thin and thick regions and observed by SEM, respectively (reproduced with permission from Appl. Phys. Lett. 83 (2003) 2064, © 2003, American Institute of Physics).
Figure 12
Figure 12
Schematic illustration of Monte Carlo simulation indicating the profile of the deposit and electron scattering inside the already grown deposit (reproduced with permission from Ultramicrosocopy 103 (2005) 17, © 2005, Elsevier, Ltd).
Figure 13
Figure 13
Tungsten tips fabricated on silicon thin film using electrons with different energies from 20 to 400 keV (reproduced with permission from Japan. J. Appl. Phys. 46 (2007) 6254, © 2007, The Japan Society of Applied Physics).
Figure 14
Figure 14
Theoretical growth of tungsten tips on tungsten point substrate simulated for 20, 200 and 400 keV electrons under idealized conditions (reproduced with permission from Japan. J. Appl. Phys. 46 (2007) 6254, © 2007, The Japan Society of Applied Physics).
Figure 15
Figure 15
(a) HAADF-STEM image of the characters ‘NIMS’ written on a Si substrate by the deposition of dots with 3.5 nm diameter using a W(CO)6 precursor and (b) a freestanding ring grown from an edge of a carbon grid into space using an FE-STEM (reproduced with permission from J. Microsc. 214 (2004) 76, © 2004, The Royal Microscopical Society).
Figure 16
Figure 16
TEM images of (a) nanodots and nanorods, (b) freestanding square frame produced from Fe(CO)5 gas, (c) electron diffraction pattern taken from the circular area in (b) and (d) EELS obtained from the same area (reproduced with permission from Japan. J. Appl. Phys. 44 (2005) 5631, © 2005, The Japan Society of Applied Physics).
Figure 17
Figure 17
(a) HAADF-STEM image of the freestanding square frame obtained from Fe(CO)5 gas after heat treatment at about 873 K for 1 h, (b) electron diffraction pattern taken from the circular area in (a) showing the formation of an α-iron phase, (c) dark-field TEM image of the square frame showing grain structures and (d) EELS obtained from the same area as (b) (reproduced with permission from Japan. J. Appl. Phys. 44 (2005) 5631, © 2005, The Japan Society of Applied Physics).
Figure 18
Figure 18
(a) SEM image of freestanding nanostructures with a desired shape on a thin silicon substrate obtained by EBID using Fe(CO)5 at room temperature, (b) enlarged image of frame in (a), (c) electron hologram and (d) reconstructed phase (interference) image in (b). The phase was amplified by a factor of 4.
Figure 19
Figure 19
SEM images of iron rodlike deposit on a W tip apex, fabricated by EBID using Fe(CO)5 at room temperature. The length of the deposit is about 600 nm (reproduced with permission from J. Mater. Sci. 41 (2006) 2627, © 2006, Springer-Verlag).
Figure 20
Figure 20
(a) Electron hologram of iron rodlike deposit on a W tip, (b) reconstructed phase image with an amplification factor of 4 and (c) the line profile of the phase distribution across the line in (b) (reproduced with permission from J. Mater. Sci. 41 (2006) 2627, © 2006, Springer-Verlag).
Figure 21
Figure 21
Partial pressure dependence of size of nanodots obtained by EBID. Dots formed with partial pressures of (a) 1×10−5 Pa, (b) 5×10−6 Pa and (c) 2×10−6 Pa, and (d) one of the dots in (c) with a size of 2.4 nm (reproduced with permission from Appl. Phys. A 78 (2004) 543, © 2004, Springer-Verlag).
Figure 22
Figure 22
Array of the smallest reported W nanodots by EBID: (a) TEM image of the array, (b) magnified image of a dot indicated by an arrow in (a), and (c) corresponding HAADF-STEM images (reproduced with permission from Surf. Int. Anal. 37 (2005) 261, © 2005, John Wiley and Sons, Ltd).
Figure 23
Figure 23
Relation between the dotsize and the irradiation time as a function of the partial pressure (reproduced with permission from Appl. Phys. A 78 (2004) 543, © 2004, Springer-Verlag).
Figure 24
Figure 24
(a) TEM image of an array of nanodots formed on Si (111)-7×7 substrates at room temperature and (b) EELS spectrum taken from the nanodot area showing the existence of carbon (reproduced with permission from J. Cryst. Growth 275 (2005) e2361, © 2005, Elsevier, Ltd).
Figure 25
Figure 25
(a) Array of Fe nanodots on clean Si substrate after annealing at 700 K, (b) high-resolution image of one of the dots showing lattice fringes and (c) its FFT image (reproduced with permission from J. Cryst. Growth 275 (2005) e2361, © 2005, Elsevier, Ltd).
Figure 26
Figure 26
TEM image of iron silicide nanorods deposited on a Si (111) substrate (reproduced with permission from Appl. Phys. Lett. 86 (2005) 183104, © 2005, American Institute of Physics).
Figure 27
Figure 27
Deposition time dependence of the rod length. Deposition times: (a) 5 s, (b) 10 s and (c) 15 s (reproduced with permission from Appl. Phys. Lett. 86 (2005) 183104, © 2005, American Institute of Physics).
Figure 28
Figure 28
Schematic drawing of a UHV Cs-corrected STEM being developed at the National Institute for Materials Science (NIMS), Japan.
Figure 29
Figure 29
Photograph of the UHV Cs-corrected STEM at NIMS.
Figure 30
Figure 30
Diagram of vacuum of UHV Cs-corrected STEM, showing four ion pumps, one titanium sublimation pump and the treatment chamber used for sample loading.
Figure 31
Figure 31
Schematic drawing of the corrector configuration. It consists of two 12-poles, two transfer lenses, one rotational lens and two sets of deflectors (reproduced with permission from Microsc. Microanal. 12 (2006) 456, © 2006, Microscopy Society of America).
Figure 32
Figure 32
Result of probe-shape simulation obtained with different Cs values for a STEM configuration. The contribution from C5 was not included.
Figure 33
Figure 33
(a) Dumbbell structure of silicon (110). In the power spectrum of image (b), 0.11 and 0.104 nm distances can be observed (reproduced with permission from Microsc. Microanal. 12 (2006) 456, © 2006, Microscopy Society of America).
Figure 34
Figure 34
Ronchigram obtained using the Cs corrector. The circle is at the 45 mrad position. The extended sweet spot area of this Ronchigram indicates that the corrector is working properly. The estimated probe size under this condition is about 0.2 nm (reproduced with permission from Microsc. Microanal. 12 (2006) 456, © 2006, Microscopy Society of America).
Figure 35
Figure 35
HAADF-STEM images of the same as-thinned SrTiO3 TEM sample taken using (a) standard STEM (JEM-2100F) with a regular vacuum and (b) Cs-corrected STEM with UHV environment.
Figure 36
Figure 36
Cross-sectional HAADF-STEM image of as-grown GaAs quantum ring in AlGaAs (Reproduced with permission from J. Cryst. Growth 301–302 (2007) 740, © 2007, Elsevier, Ltd).

Similar articles

See all similar articles

Cited by 4 articles

LinkOut - more resources

Feedback