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projects:semiconductors:log [2026/07/18 22:03] – q3kprojects:semiconductors:log [2026/08/03 21:05] (current) – [Day 2026-07-31 (q3k, rahix)] q3k
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 > //This page is a lab notebook. It documents the work done in the lab and our thoughts, theories, and findings related to it. Everything you read here is work in progress and not final results. We believe it is best to have our lab notes out in the open, because it gives more detailed insight into what worked for us and what didn't. Of course you can also use this page to follow our progress!// > //This page is a lab notebook. It documents the work done in the lab and our thoughts, theories, and findings related to it. Everything you read here is work in progress and not final results. We believe it is best to have our lab notes out in the open, because it gives more detailed insight into what worked for us and what didn't. Of course you can also use this page to follow our progress!//
 +
 +==== Day 2026-07-31 (q3k, rahix) ====
 +Experimented with our coating process a bit more by attempting to chrome a piece of toilet paper. We scientifically mounted it on a JEOL sample stub and then attached it to an aluminum foil holder with copper tape:
 +
 +{{:projects:semiconductors:20260731_mounted-tp.jpg?400|}}
 +
 +For coating, we used new process parameters to see how well it works out.
 +
 +Parameters: DC sputtering, 100W, Cr target, 10SCCM Ar, 2.6x10-2mbar, 30 seconds.
 +
 +Coating worked great, here is the result:
 +
 +{{:projects:semiconductors:20260731-chromed-tp.jpg?400|}}
 +
 +Viewed it under the SEM. Here are a few shots we got:
 +
 +{{:projects:semiconductors:20260801-sem-tp-1.png?400|}}
 +{{:projects:semiconductors:20260801-sem-tp-2.png?400|}}
 +{{:projects:semiconductors:20260801-sem-tp-3.png?400|}}
  
 ==== Day 2026-07-17 (q3k, guests) ==== ==== Day 2026-07-17 (q3k, guests) ====
  
-Experiments with DC sputter deposition of Cr in 'plasma process' mode and MFC.+Experiments with DC sputter deposition on our [[equipment:edwards-306:start|Edwards AUTO 306 Coating System]] of Cr in 'plasma process' mode and with MFC (mass flow controller).
  
-Flow now through mass flow controller. Controlled over DE9 port by providing +/-15V and a 0-10V control signal. 10V == 100SCCM.+Flow rerouted through mass flow controller (Ar line moved from needle valve to Ar MFC). Controlled over DE9 port by providing +/-15V and a 0-10V control signal. 10V == 100SCCM.
  
 **Process parameters:** **Process parameters:**
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 **Best results so far:** (good balance between plasma size and speed) 1-2 min, 100W, 2.6 * 10^-2 mbar (~10SCCM). Higher Ar pressures limited plasma size considerably. **Best results so far:** (good balance between plasma size and speed) 1-2 min, 100W, 2.6 * 10^-2 mbar (~10SCCM). Higher Ar pressures limited plasma size considerably.
  
-Process used:+**Process used:**
  
   - Insert sample, press 'process' or 'cycle'.   - Insert sample, press 'process' or 'cycle'.
   - Wait for machine to reach 5*10^-5 or lower.   - Wait for machine to reach 5*10^-5 or lower.
-  - Press process and hold. Ensure hold LED is blinking. Machine will display 0*10^-4 mbar as that's the lower bound of the (pirani?) gauge in process mode. +  - Press 'process' and 'hold' shortly after. Ensure hold LED is blinking. Machine will display 0*10^-4 mbar as that's the lower bound of the (pirani?) gauge in process mode. 
-  - Open MFC to 10SCCM (1V on control line). +  - Open MFC to 10SCCM (1V on control line). Pressure should rise to 2.6*10^-2 mbar. 
-  - Start DC PSU at 100W. Wait for plasma to turn blue. Purge (with plasma off) for a few minutes first if line had air in it.+  - Reset the DC PSU interlock on the rack panel. INTLK on DC PSU should light on indicating the PSU is ready to start. 
 +  - Start DC PSU at 100W. Wait for plasma to turn blue. Purge (with plasma off) for a few minutes first if line had air in it and plasma is continuously red/pink.
   - Swing sample into plasma, start 1 minute timer.   - Swing sample into plasma, start 1 minute timer.
-  - Stop DC PSU, close MFC.+  - Stop DC PSU, close MFC. Pressure should drop back down to the 10^-4 - 10^-5 mbar regime.
   - Vent.   - Vent.