1. Helium Ion Microscopy – Extending the
Frontiers of Nanotechnology
Giulio Lamedica
Assing SpA / Zeiss Microscopy

2. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFab Technology•
Conclusions•
Introduction•
More Applications•

3. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFAab technology•
Conclusions•
Introduction•
More Applications•

4. 4
As the beam is raster scanned
across the sample, secondary
electrons are generated which are
detected by ET Detector ….
Image
Formation
HIM Image

5. BS
PB
SE1 SE2
SE3
Pole piece
Resolution in CPM
BSP
 Probe Size
 Interaction VolumeSE1/SE2)

6. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFAab technology•
Conclusions•
Introduction•
More Applications•

7. 7
Superposition of the aberration discs
0
1
2
3
4
5
6
7
8
9
10
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Resolution and Probe Size – Electron Beam
Probe Size:
3
5.0 iSS Cd Spherical aberration:
iCC
U
U
Cd 

Chromatic aberration:
i
dd


6.0Diffraction Error:
Demagnified source: gSo dMd 
i
i [mrad]
dp[nm]
  2222
dCSgP ddddMd 

8. 07.10.2013
Page 8
Carl Zeiss NTS, Peter Gnauck
1,00E-06
1,00E-04
1,00E-02
1,00E+00
1 10 100 1000
U [kV]
Wavelength[nm]
Resolution and Probe Size
He+
Ga+
e-

9. 9
0
1
2
3
4
5
6
7
8
9
10
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Resolution and Probe Size – Helium Ion Beam
Probe Size:   2222
dCSgP ddddMd 
3
5.0 iSS Cd Spherical aberration:
iCC
U
U
Cd 

Chromatic aberration:
i
dd


6.0Diffraction Error:
Demagnified source: gSo dMd 

i [mrad]dp[nm]
•The Helium Ion Microscope has a half angle (/2) of
0.5mrad compared to a typical SEM of 5-10mrad
• The Helium Ion Microscope has a theoretical probe
size of 0.2nm and a demonstrated probe size of
0.24nm (product specification <0.35nm)

10. No diffraction limitations (MHe/Me = 7289)
Helium ions are more particle-like in nature due to higher mass (compared to electrons)
1
Key Attributes of Helium Ion Microscopy
10
He ions have extremely little diffraction effects
Imaging of small
aperture with He ions
Imaging of small
aperture with He ions
Diffraction limited
image
No diffraction
limitations
Wavelength ~ 0.01 nm
Wavelength ~ 0.0001 nm
MHe/Me = 7289
80X smaller at all energies
2
2
1
1
2
cm
eUeUm
h
He
He



11. Key Attributes of Helium Ion Microscopy
11
Spot size = 0.8 nm
Electrons
Very high lateral resolution in images
Sub-nm probe size and very narrow interaction volume
2
He ions
Silicon Sample30 nm
1 keV e-beam into Silicon: Image
suffers from large interaction
volume at the surface. Many
SE’s are really SE2.
30 keV Helium into Silicon:
Beam is well collimated
beyond the SE escape depth.
Recoil contribution is
negligible.
Spot size = 0.35 nm

12. Key Attributes of Helium Ion Microscopy
12
Surface sensitive imaging
Secondary electrons get generated from within 3-5 nm of the sample surface
3
Electrons He ions
Silicon Sample30 nm
1 keV e-beam into Silicon: Image
suffers from large interaction
volume at the surface. Many
SE’s are really SE2.
30 keV Helium into Silicon:
Beam is well collimated
beyond the SE escape depth.
Recoil contribution is
negligible.
Secondaryelectron
escapedepth
Volume from which
SE’s are generated
Volume from which
SE’s are generated

13. High SE yield means low ion doses can generate excellent images
Helium ions generate many secondary electrons per ion
4
Key Attributes of Helium Ion Microscopy
13
Electrons He ions
Silicon Sample30 nm
He ions product 4-7 times as
many secondary electrons
30 keV Helium into Silicon:
Beam is well collimated
beyond the SE escape depth.
Recoil contribution is
negligible.

14. Key Attributes of Helium Ion Microscopy
14
Electrons
5X-10X greater depth of focus in the images
Helium ion beam has 5X lower convergence angle than FESEM
5
He ions
Silicon Sample30 nm
Convergence
Angle = 0.020

Best
Focus
Best
Focus

15. Key Attributes of Helium Ion Microscopy
15
Extremely easy to get high resolution images of insulating samples without complex preparation
Insulating samples are only positively charged under helium ion beam
6
The sample interaction volumes and the positive and negative charge distributions (+,-)
arising from imaging with the SEM and with the HIM. SE1 are secondary electrons created
from the primary beam. SE2 are secondary electrons created from backscattered
electrons (BSE)
0 nm
10 nm
300 nm
Helium @ 30 kVSEM @ 0.5 kV
-
SE2
SE2
SE1
BSE
-
--
++++ +
+
SE1
SE1
+++ ++
--
-
-
-
Bulk Charging
Surface
Charging
Positive surface
charging only -
easily neutralized
by electron flood
gun!
Electrons He ions

16. Why Helium Ion Microscopy?
Very high lateral resolution in images
Sub-nm probe size and very narrow interaction volume
1
No diffraction limitations
Helium ions are more particle-like nature due to higher mass (compared to electrons)
2
Surface sensitive imaging
Secondary electrons get generated from within 3-5 nm of the sample surface
3
High SE yield means low ion doses can generate excellent images
Helium ions generate many secondary electrons per ion
4
5X-10X greater depth of focus in the images
Helium ion beam has 5X lower convergence angle than FESEM
5
16
Extremely easy to get high resolution images of insulating samples without complex preparation
Insulating samples are only positively charged under helium ion beam
6

17. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFAab technology•
Conclusions•
Introduction•
More Applications•

18. What is Ion Beam Milling?
18
Schematic showing material being
sputtered away by helium beam
Illustration from “Gas-assisted focused electron beam and ion beam processing and fabrication”, J. Vac. Sci. Technol. B 26(4), Jul/Aug 2008
Helium ion beam can remove material …
(1) … at a controlled rate
(2) … with high fidelity
(3) … from within 5 nm of beam impact point
Complex shapes and arrays of shapes can be milled
using patterning engine.
APPLICATION AREAS
(1) Nanopore fabrication in thin films
(2) Precision milling of thin films
(3) Optical and magnetic metamaterial research
Ion beam milling utilizes the sputtering capability
of ion beam to remove material

19. Why is Helium Ion Beam Suitable for Nanofabrication?
Remove material by sputtering
Helium ions are much more massive than electrons
1
Remove material at a controlled rate
Helium ions are less massive than gallium ions
2
Remove material locally
Helium ions sputter material from within 5 nm radius of beam impact point
3
Chemically enhanced etching and deposition at length scales not achievable with Gallium FIB
Helium ions can induce etching and deposition reactions at surface with precursor gases
4
No proximity effect in helium ion beam lithography
Helium ions scattering profile in resists is narrow conical with low backscatter
5
High sensitivity, better contrast than e-beam lithography
Helium ions can expose resists in 5X smaller doses
6
19

20. Ion Beam Milling Comparison between Helium and
Gallium FIB
20
1 10 20 30 100 nm
Ga FIBHe FIB
Helium FIB
Type of Ion Source Gas Field Ion Source
Minimum feature size
Spot size (30 kV)
Diameter of sputtered
region in gold (spot)
1 nm
0.35 nm
2.6 nm
Gallium FIB
Liquid Metal Ion Source
25 nm
5 nm
20 nm
Suitable for milling Small structures Large structures

21. Nanofabrication Examples …
21
Graphene Photonics
DNA Sequencing
Nanopores
Lithography Nanopillars

22. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFAab technology•
Conclusions•
Introduction•
More Applications•

23. He Ion Beam Milling
Graphene Research
Research
Area
Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional
(2D) honeycomb lattice, and is a basic building block for graphitic materials. It has
extraordinary properties:
(1) Electronic (2) Optical (3) Thermal (4) Mechanical
2010 Nobel Prize in Physics awarded for groundbreaking experiments with graphene
Research
Applications
Nanoribbons
Transistors
Optical modulators
Integrated circuit
Transparent electrodes
Ultracapacitor
Chemical and electrical sensors
Structure

24. Helium Ion Microscopy
Imaging of Graphene
24
Material Science
Challenge How do you see graphene CVD growth?
Zeiss Solution Helium Ion Microscopy: highly surface sensitive imaging
The grain boundaries of
the graphene can be
identified as ridges on the
surface.
CVD grown graphene
monolayer on copper.
Sample Courtesy: University of Houston
Research

25. Helium Ion Microscopy
Imaging of Graphene
Material Science
Challenge How do you see quality of Graphene trasferred on Silicon ?
Zeiss Solution Helium Ion Microscopy: highly surface sensitive imaging
Research

26. University of Bielefeld (D)
Helium Ion Microscopy
Imaging of Graphene

27. Graphene Machining for Quantum Confinement
The bandgap in a graphene
ribbon increases as the
ribbon width decreases
In order to increase bandgap
above room temperature
thermal energy (25
meV), confinement of ribbon
to less than 20 nm is desired.
M. Han, B. Özyilmaz , Y. Zhang., P Kim, Phys; Phys. Rev. Lett. 98 (2007) 206805
Graphene nanoribbons
bandgaps can be modulated

28. Current Solutions
• Lithographic patterning has been applied, but resist deposition and then
removal can alter graphene electronic properties.
• Ga FIB milling produces too much damage to be useful (image)
• E-beam bond damage, followed by chemical etch, cannot produce
sufficiently sharp feature edges.
• Need: low damage, precise, method that does not touch graphene
intended for pattern.
Gierak et al., Microscopy Today (2009)

29. FOV 500 nm
1.86 E18 1.99 E18
* All units in Ions/cm2
2.39 E18
2.13 E18
2.53 E18
2.93 E18
2.26 E18
2.63 E18 2.79 E18
5-6 nm width
Direct Patterning of Graphene:
5 nm Features
Graphene created by the exfoliation method (1-3 layers thick)
Created on SiO2 over cylindrical holes on surface.
Ion milling carried out on the suspended area.
FOV 100 nm
2.79 E18
Dr. Dan Pickard, National University of Singapore

30. 4.8 E18
2.9 E18
4.8 E18
Dose (ions/cm2)
5nm width
10nm width
20nm width
Vertical
FOV 700nm
Direct Patterning of Graphene:
Ribbon Width Control
• Pattern generator (Nabity ) used
to define milling structures
• External control of column
• 700 nm vertical field of view
• Milling proceeded simultaneously
down both sides of ribbon to
maintain strength
Dr. Dan Pickard, National University of Singapore

31. 10nm wide ribbon
3.5 microns long
20nm wide ribbon
3 microns long
Direct Patterning of Graphene
• 20 nm and 10 nm wide
suspended ribbons
• 4 µm field of view
• Aspect ratio up to 350X
FOV 4 µm
Dr. Dan Pickard, National University of Singapore

32. • Graphene layer (could be multiple
layers) on SiO2 substrate
• Goal: creation of a quadrupole
quantum dots structure
• 4 dots, with 4 electrodes to control
the occupancy of dots
• Created by bitmap imported into
Orion patterning interface
• 10 nm gaps have been created
• Next required step: pattern
electrodes to the device for electrical
testing (using beam chemistry!)
Graphene Milling on a Substrate
Creation of features with high machining precision
Graphene on SiO2
Courtesy of Stuart Boden, University of Southampton

33. Graphene Nanoribbons
Why Helium Ion Milling over other methods?
• Fast
• Non-destructive
• Contamination free
• Extends limitations (down to 5-6 nm width)
• Capable of complex geometries
• External control of column

34. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFAab technology•
Conclusions•
Introduction•
More Applications…•

35. Carbon Nanotubes – Large Depth of Focus
200nm
Research Single walled Carbon nanotubes on Si-Ge catalyst imaged with a 70 tilt
Challenge study of the growth dynamics that progress parallel to the substrate in this case
Zeiss Solution
long depth of focus allows the CNT attachment to the catalyst to be imaged deep
into the background Contrast for low atomic weight material at high resolution
Sample courtesy Prof.
H.N.Rutt, Univ. of
Southampton

36. Helium Ion Microscopy
Carbon Nanotubes
Research CNT with Sn and Pd nanoparticles
Challenge How do you evaluate nanoparticle distribution?
Zeiss Solution Helium Ion Microscopy: Topographical and Material contrast

37. Nanowires – Strong Materials Contrast
100
nm
Sample courtesy Princeton
University
Research
Nanowires in the beginning of growth phase
Catalyst array in substrate
Challenge Study the dynamics of the growth in this system with greater detail
Zeiss Solution
Strong material contrast clearly delineates the nanowires but without saturation of
the image

38. Helium Ion Microscopy
SAM Modification
Research
Nitro-biphenyl-thiol (NBPT) self-assembled monolayer on gold, Electron beam
patterning via stencil mask converted terminal nitro group to amine
Challenge How to identify chemical changes?
Zeiss Solution
Helium Ion Microscopy: Topographical and Material contrast possible studies of this
chemical lithography which otherwise requires AFM, which has throughput limitations

39. Helium Ion Microscopy
Imaging of Uncoated Polymers
39
200 nm 200 nm
SEM HIM
Research Bioengineering (PLLA/hydroxyapatite composites for large bone defect healing)
Challenge How do you visualize biomineral growth on sensitive polymer surfaces?
Zeiss Solution Helium Ion Microscopy: damage –free imaging
Hydroxyapatite
crystal on PLLA
Charging and
sample damage

40. Research Material Science
Challenge How do you visualize at high magnification low weight materials ?
Zeiss Solution HeIM: Good contrast for low weight materials @ over 1MX (0.29 nm res)
Helium Ion Microscopy
Carbon Black

41. Helium Ion Microscopy
Imaging of Inner Ear Tectorial Membrane
41
Bioscience
Challenge How do you see the complex morphology of tissue nanostructures?
Zeiss Solution Helium Ion Microscopy: charge neutralization technology allows clear view
Sample Courtesy: NIH
Research

42. Ion Beam Milling
Metamaterial Research
42
Research
Area
Metamaterials are engineered materials with properties that are not found in natural
materials. Also known as “left-handed” media, “Negative refractive index” media
Metamaterials gain their properties from structure rather than composition, using
small periodic (1D, 2D or 3D) inclusions (holes, lines, space etc.) in bulk material to
create effective macroscopic property.
Electromagnetic
Waves
Visible light
Infrared
Terahertz
Microwaves
Radiowaves
Research
Applications
Terahertz materials
Photonic materials
Plasmonic materials
Metamaterial antennas
Nonlinear materials
Metamaterial absorber
Superlens
Cloaking devices
Working
Principle
The objective is to create a
“structured” metamaterial that
will exhibit desired properties
when electromagnetic waves
interact with respect to
(1) Propagation (3) Absorption
(2) Transmission (4) Reflection
Metamaterial

43. Ion Beam Milling
Metamaterial Research
43
Traditional
Methods
 Lithography
 Layer by Layer or Self-assembly based methods
Zeiss Ion
Beam Milling
Solution
Drawbacks
Multi-step – have to rely on success of multiple steps
Tedious – numerous iteration of process development steps
Structure is big
enough to make
with Ga FIB
20 nm Gold (evaporated)
5 nm ITO
Glass Substrate
Zeiss Ga FIB Solution: Array fabricated in 20 minutes
Source: “Focused-Ion-Beam Nanofabrication of Near-Infrared Magnetic Metamaterials”, Adv. Mater. 2005, 17, 2547–2549

44. Ion Beam Milling
Metamaterial Research
44
Going Smaller
By making the shapes in the array smaller, one can modulate the frequency
response of the metamaterial.
Example: As array element is made smaller, transmission of shorter wavelengths is suppressed.
Long
wavelengths
blocked
Medium
wavelengths
blocked
Short
wavelengths
blocked
How does
one make
smaller
structures?
Helium Ion Beam Milling, (Neon Ion Beam Milling)

45. Ion Beam Milling
Complex Shapes for Plasmonics
45
Research
Area
Plasmonics, Photonics, Sensors
Challenge
How does one make small enough structure in metal film that will exhibit plasmon-
enhanced transmission at desired wavelength?
Zeiss Solution Helium Ion Beam Milling
Theory: Fractal shapes
enhance plasmon-assisted
transmission*
*Source: “Fractal extensions of near-field aperture shapes for enhanced transmission and resolution”, Optics Express, 2005, 13, 636-647
** Courtesy: Dan Pickard, NUS
First fractal iteration based
on Hilbert Curve
Second Fractal iteration
based on Hilbert Curve
50 nm
Helium ion
beam milling
can make
complex
structures Au Al Ag
**

46. Ion Beam Milling
Technology Comparison • Ga FIB vs. Helium Ion Beam
46
1 10 20 30 100 nm
Ga FIBHe FIB
* Courtesy: Dan Pickard, NUS

47. What is Ion Beam Induced Etching?
47
Schematic showing material being
etched away by He beam in the
presence of precursor gas molecules
Illustration from “Gas-assisted focused electron beam and ion beam processing and fabrication”, J. Vac. Sci. Technol. B 26(4), Jul/Aug 2008
When an etch gas (such as XeF2) adsorbs on a surface,
enhanced etching/material removal will occur if the
surface is scanned by helium ion beam.
APPLICATION AREAS
(1) Photomask repair
(2) Removal of excessive amounts of material
Material removal in the scanned region
He+

48. Ion Beam Induced Etching
Photomask Repair
48
Area Photomasks for lithography
Challenge How do you increase throughput in EUV photomask repair?
Zeiss Solution Helium Ion Beam Induced Etching
TaN Absorber Layer
No XeF2 XeF2 Present
TaN Absorber Layer
 12 nm wide lines at 25 nm pitch
 Etching speed significantly
enhanced by XeF2 precursor
 Same exposure conditions
(areal dose / scan repeats etc.)Introduce XeF2
100 nm
Source: Diederik Maas, TNO

49. What is Ion Beam Induced Deposition?
49
Schematic showing material being
deposited by He beam in the presence of
precursor gas molecules
Illustration from “Gas-assisted focused electron beam and ion beam processing and fabrication”, J. Vac. Sci. Technol. B 26(4), Jul/Aug 2008
When a deposition precursor gas adsorbs on a surface,
material will be deposited if the surface is scanned by
helium ion beam.
APPLICATION AREAS
(1) Deposition of conductive lines and pads
(2) Failure analysis of integrated chips
Material deposition in the scanned region
He+

50. Ion Beam Induced Deposition
Application • Vertical Nanopillars
50
Area AFM probes tips, Hard mask for lithography
Challenge How does one create vertical nanopillars?
Zeiss Solution Helium Ion Beam Induced Deposition
Platinum Nanopillars
(a) At low currents
(b) Blow-up of the
enclosed pillar, the
yellow ellipse is the
estimated pillar
bottom
(c) At high currents
Source: Nanotechnology 21 (2010) 455302 (7pp)

51. What is Ion Beam Lithography?
51
When resists such as HSQ and PMMA are
exposed to ion beams, their solubility
changes and can be used for patterning.
Just like electron beams, ion beams
can be used for lithography
He+
He+
Develop
Develop

52. Ion Beam Lithography
Sub-10 nm Lithography
52
Research
Area
There is an interest in making smaller and smaller lines at a tighter pitch using
lithography to keep up with Moore’s law.
State-of-the-art
E-Beam Litho
Best results : 6 nm lines at 12 nm pitch
Half-pitch = 5 nm
Dose = 4000 e-/nm
Half-pitch = 6 nm
Dose = 4400 e-/nm
Half-pitch = 8 nm
Dose = 5000 e-/nm
Half-pitch = 10 nm
Dose = 6300 e-/nm
Source: Karl Berggren, MIT
Reaching limits of EBL ….

53. Ion Beam Lithography
Sub-10 nm Lithography
55

54. Ion Beam Lithography
Neon Beam Lithography
56

55. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFab Technology•
Conclusions•
Introduction•
More Applications•

56. 58
Orion Plus

57. He – Ne Gas Field Ion Source (GFIS)
Single column – dual source concept
 Probe Size; Probe Current:
 He – 0.5 nm; 0.1 - 5 pA
 Ne – 1.9 nm; 0.1 - 2.5 pA
 Accelerating Voltage
• 10 – 35 kV
 Switching time between gases
ET
Detector
Electron
Flood Gun
Sample
SE
Helium + Neon
Target Specs.
 Higher sputter yield (30% greater
than helium)
 Shallower penetration depth
 Higher SE yield compared to He -
3X faster resist exposure than He
 Improved deposit quality – Metal
deposit resistivity equivalent to Ga
Neon Beam Benefits
High resolution imaging using He combined
with
High fidelity nanostructuring using Ne
59

58. 9/20/2012 PageCarl Zeiss NTS LLC , Bernhard Goetze
Cryogen
ic
Cooling
Gas InletHigh Voltage
High Speed
Camera
Phospho
r Screen
Gas Field Ion Source

59. 61
The Technology Behind It
Individual atoms are stripped away from
the source until an atomic pyramid is
created with just three atoms at the very
end of the source tip – a configuration
called the trimer.
Once the trimer is formed, the tip is
maintained under high vacuum and
cryogenic temperatures with helium or
neon gas flowing over it.
The helium or neon atoms are attracted to
the energized tip where they are ionized.
With ionization happening in the vicinity of
a single atom, the resulting ion beam
appears to be emanating from a region
that is less than an angstrom in size.

60.  FIM tip created via chemical
etching
 ALIS tip formed with additional
reshaping
 3 atom shelf called the “trimer”
created through field evaporation
 Single atom selected to form the
final probe
 Results in a sub-angstrom virtual
source with high brightness (4x109
A/(cm2 sr)) and low energy spread
(<1eV)
The Atomic Level Ion Source
62

61. ORION NanoFab– The Column
9/20/2012

62. Bulk Milling with Ga
Multi-ion Beam Machining in ORION NanoFab
Intermediate Milling with NeFinal Milling with He
Sample: Gold film on Glass substrate
Ga Milling
He Milling
Ne Milling
64

63. Nanofabrication
Why He ions for Imaging?
HeiM on Graphene
Summary
•
•
•
Orion NanoFAab technology•
Conclusions•
Introduction•
More Applications•

64. The ORION NanoFab Platform
• Configurable architecture to
address specific imaging and
nanofabrication applications.
• High Resolution Imaging on
insulating samples – ideal for life
science and polymer imaging
applications.
• 3D Nanofabrication of sub-10nm
structures.
• Precise Machining with He/Ne
beams and Rapid Prototyping
with Ga beam – only platform
offering unique combination of
three different ion beams.
Sample
Helium + Neon
Ga XRE

65. Stereocilia
9/20/2012 67
Carl Zeiss NTS LLC , Bernhard Goetze
200 nm
HIM: Unsurpassed Resolution 0,24nm

66. Carbon Nanotubes(Provided by Prof. Brendan Griffin Univ. W. Australia)
CNT
HIM: Low Damaging Effect

67. MEMS
HIM: High Depth of Field

68. Collagene
HIM: Effective Charge Compensation

69. (Provided by Prof. Brendan Griffin Univ. W. Australia)
CNT
HIM: Surface Details

70. 9/20/2012 72Carl Zeiss NTS LLC , Bernhard Goetze
Collecting Duct
HIM: High Resolution and Elevated Surface Details

71. 500nm
Catalyst: Pd on ZnO nanowires
73
HIM: High Depth of Field

72. Bacteria
9/20/2012 74Carl Zeiss NTS LLC , Bernhard Goetze
200 nm
HIM: Minimal Sample Preparation

73. HIM: Nanofabricaation with Ga ions
75
TEM lamella S/C

74. 200nm
76
Al bump su Silicio
HIM: Nanofabricaation with Neon ions

75. 100nm
~4nm gap
TEM Image
77
Plasmonic Devices
HIM: Nanofabricaation with He ions

76. Bulk Milling with Ga
Multi-ion Beam Machining in ORION NanoFab
Intermediate Milling with NeFinal Milling with He
Sample: Gold film on Glass substrate
Ga Milling
He Milling
Ne Milling
78
HIM: Nanofabricaation with Multiple Beam
Plasmonic Devices

77. 79