Differences

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--- e-beam_evaporator [2025/06/13 13:54] – [Aftermath] wigbout
+++ e-beam_evaporator [2025/12/03 16:13] (current) – [Common errors] fabian
@@ Line 182: / Line 182: @@
    * Open the Ar-valve.
    * Wait until the chamber pressure is stable.
-   * Set your desired Argon flow (e.g. 2.5 sccm)
+   * Set your desired Argon flow (e.g. 3.0 sccm)
    * Check all the settings from the ion beam (voltages, etc.)
    * Press ''discharge''
@@ Line 195: / Line 195: @@
    * Close Ar-valve.
    * Put back the sampleholder to the original position, facing downwards.
+=== Etch rate ===
+The etch rate in theory is about half of the etch speed of the ion beam etcher in the clean room. Beam diameter of the clean room IBG is approx. 4 cm, beam diameter of the e-beam IBG is a little below 10 cm. Beam current of the clean room IBG is ~7.5 mA, beam current in the e-beam IBG is ~15 mA.
+The intensity is given as beam current divided by beam area (I/r^2π) where r is the radius of the beam (half the beam diameter).
+In practice, however, the etch rate is about 1/3 the etch rate of the clean room ion beam etcher (tested 02/12/2025 with 60 nm of Nb, capped with 5 nm Pt).
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@@ Line 251: / Line 259: @@
-==== Common errors ====
+===== Common errors =====
+   * **IBG discharge failure.** If the ion beam gun power source shows the HLP26 or HLP27 error, reset the power source by pressing the button the says ''Discharge Enable / Standby'' with the label ''Reset'' next to it. A common cause for a discharge error is insufficient Ar pressure. A pressure of 3.8e-4 mbar is the lower boundary for a stable emission. At 3.7e-4 mbar to 3.6e-4 mbar there are insufficient Ar atoms for the IBG to maintain a stable discharge. An Ar flow rate of 3.0 sccm is sufficient, 2.5 sccm is on the lower end and might not be enough. **Note:** Pressure typically drops by 0.1e-4 mbar to 0.2e-4 mbar during etching over a scale of 1 to 3 minutes. Keep this in mind when selecting flow rate.
-   * Discharge failure? If the power source shows the HLP26 or HLP27 error, reset the power source by pressing the button the says ''Discharge Enable / Standby''