1. SEM In-situ Experiments for Breakdown Study
Tomoko Muranaka
T. Blom*, K. Leifer*, V. Ziemann
Department of Physics and Astronomy
Department of Engineering Science*
Uppsala University
Sweden
Ångström Laboratory, Uppsala, Sweden
November 30, 2010
Supported by the 7th European Framework program EuCARD under grant number

2. Ideas of Experiments
Basic Idea: Reproduce high gradient electric field conditions in micro meter range, 1 GV/m = 1 kV/μm
SEM Chamber
Sub μm
Gap
meas.
Needle V
Bias
Sample A
pA current
meas.
Scanning Electron Microscopes (SEM) open an opportunity to investigate local processes during breakdown
“Mesoscopic” field emission and breakdown measurement and observation
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3. Experimental Setup Experimental setup Philips XL30 ESEM FEG
Cu sample: 1.2 mm diameter, 0.5 mm thickness
A piezomotor (Piezo LEGS® Linear 10N Non Magnetic Vacuum)
A tungsten needle attached to the rod of piezomotor
Positive / Negative bias voltage on the needle
Setup in SEM at 0 deg. tilt (drawing)
Gap calculator program
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Setup in SEM at 30 deg. tilt (drawing) 3
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4. Focused Ion Beam to go further
SEM
FIB
Omniprobe
Sample
position
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FEI Strata DB235 4
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5. In-situ Breakdown W tip to flat surface (≈ 1μm)
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W tip to flat surface (≈ 1μm)
Up to -1000V on the tip 5
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6. Damage inside the surfacePt
Interesting area
FIB
Pt coating
Staircase milling
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7. Cross Section of the BD Area (1)
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8. Cross Section of the BD Area (2)
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9. Surface Manipulation
3D structure: By controlling gallium ion beam size and intensity, one can ”mill” a surface of samples with nm resolution and create surface corrugations, pillars and tips.
Images from two different angles: The image of the sample can be observed both by SEM and FIB simultaneously. FIB beam line is at an angle of 52 degrees to the SEM beam line.
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10. Summary & Outlook Breakdown in the SEM Accurate gap control
Cross section images of BD area
Artificial surface preparation by FIB
Field emission measurement
Cu tip - Cu surface
Well defined tip (sharp - blunt)
Geometrical dependence (surface feature)
Controlled breakdown
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