ZEISS 5 First Operating Steps | 5.5 Modifying Gun Parameters and Optibeam Mode
5.5.3 Setting the Probe Current
Info
The maximum achievable probe current depends on the currently selected EHT and the in-
stalled aperture configuration.
Procedure
1. In the SEM Controls panel, select the Gun tab.
2. Double-click the I Probe readout.
à The I Probe window is displayed.
3. In the input field, enter the desired value.
5.5.4 Measuring the Probe Current
Measuring the probe current using the Faraday cup ensures that the current displayed in the soft-
ware equals the incident probe current. The Faraday cup consists of a strongly absorbing material
with a cavity covered by a small aperture. If the beam is focused in this cavity, no secondary elec-
trons and no backscattered electrons leave the Faraday cup.
Parts and Tools
Faraday cup (348342-8055-000)
Procedure
1. Load the Faraday cup into the specimen chamber.
2. Evacuate the specimen chamber.
3. Switch on the gun.
4. Switch on the EHT.
5. Set a magnification that allows transmission of the complete electron beam through the
aperture into the cavity of the Faraday cup.
6. From the Panel Configuration Bar, select Specimen Current Monitor.
à
The Specimen Current Monitor window is
displayed.
7. Move the stage to the position of the Faraday cup.
8. Acquire an image of the Faraday cup.
9. Activate the Spot checkbox.
à Green crosshairs are displayed on the image. The crosshairs indicate the position of the
beam spot.
10. Grab the crosshairs and move them into the hole of the Faraday cup.
11. Activate the SCM On checkbox.
à The probe current is measured continuously.
à The measured probe current is displayed in the Specimen I readout.
5.5.5 Selecting the Optibeam Operation Mode
EVO can be operated in different Optibeam operation modes, depending on the type of applica-
tion. Based on the requirements for probe current, working distance, etc., Optibeam determines
the optimum lens settings to achieve the best performance from the column.
The following modes are accessible in HV mode (when no aperture is fitted) or when the EasyVP
aperture is fitted:
Instruction Manual ZEISS EVO | en-US | Rev. 10 | 354706-0780-006 81
To Next Page
Loading...
