Procedures of HIM Patterning

Patterning

1) Turn on the NPVE Software

2) Under the "Imaging (GFIS)" >> Select Ultrafast >> Grab
Select “Ultrafast” so that your sample will not be damaged much by the He beam.

3) Draw Patterns on your samples
You shall explore the function of those buttons below.
You can select "Void" and "Outline", and also the geometry dimension.
You can also select the direction of patterning.
You can also draw a pattern and select "Array Builder".

4) Select the Dose
The typical dose of Au nanoplates with thickness 30-50 nm required dose of 1.7-1.9 nC/um^2
You can select different units of dose. You shall test the test out the dose at the corner of your sample.

5) Start Patterning
You can change the ID number of patterns.
You can see the calculated time of patterning.
You can select to pattern the drawn geometric in "Parallel Patterns" or not.
You can stop the patterning anytime during the milling process. Stop it once your sample is fully drilled.

Drift Correction

1) Click the Drift button on the NVPE panel.

2) Automatic Drift Correction >> Wait for end of sequence

3) Under the Options:
(i) Auto pixel size: 3.0 nm
(ii) Dwell time: 1.0 micron x 1
(iii) Min confidence: 70%

4) Select Target Area >> Locate a unique position with your mouse >> Monitoring (to see how far it drifts per min)

5) Automatic Drift Correction: 60s (approximate via "Monitoring")

Resolution of Patterning

• The typical resolution of the He ions beam is about 6-10 nm.
  The typical resolution of the Ne ions beam is about 10-20 nm.

• We may use a 0.2 pA-0.4 pA He ions beam to pattern very sensitive samples (e.g., polymer-based resist).
  We may use a 1. 0 pA He ions beam to pattern most of the samples (e.g., gold nanoplates).
  We may use a 3-7 pA He ion beam to draw large area patterns (e.g., 0.5 micron meter^2).

• Depending on the current, the probe size of He will vary. The probe size of the He ions beam is about 0.5 nm for 1.0 pA.

• The resolution of patterning can be higher for suspended samples, for example, exfoliation graphene oxide.
  Due to the backscattering, the patterning of bulk gold will have less resolution.