| University | Search | News | A-Z Index | Contact Us
Quick guide to the Metal Evaporator
| | ||||
| ||||
| | ||||
Quick guide to the Metal Evaporator |
| |||
The Metal Evaporator uses high voltages to melt the metals to be evaporated in baskets whilst in a high vacuum. This causes them to evaporate and to be deposited on the substrate below. Often the substrate has a covering mask or template in order to produce a design.
In our lab we are producing gold electrodes on glass. To get gold to stick to glass, and not be easily rubbed off, a intermediary is required - usually chromium, but titanium can also be used. Chromium is first evaporated onto the substrate from one basket, followed by gold. Instead of gold, other metals, e.g. silver, can be used.
1) Switch evaporator on.
2) Undo retaining nuts.
3) Press "Stop". Evaporator will vent.
4) Remove blast shield, open lid and remove top seal.
5) Remove glass chamber, being very careful not to damage, and remove lower seal.
6) Check the chromium level in the Cr basket. If the metal chip looks small place more in (you don't want it to run out mid-evaporation). NB: Wear gloves - don't allow organic material (e.g. stuff on your hands) to get into the chamber.
7) Place gold in basket.
8) Replace seals and glass chamber.
9) Pull out side door and place substrate onto shelf, on a tray if necessary.
10) Close side door and tighten retaining nuts. Ensure there are no gaps.
11) Press "Start", then press "Enter" twice. Chamber will begin to evacuate. Ensure there are no leaks.
12) Wait until the pressure is approximately 3x10-6 (The lower the better). Gold sticks to chromium much better under high vacuum conditions.
13) Choose "Source B", press "Enter". You will see a warning - follow it - DO NOT LOOK DIRECTLY AT THE FILAMENT OR THE SOURCE BEING EVAPORATED, YOU WILL DAMAGE YOUR EYES.
14) Slowly turn the knob until a blue plasma is seen below the shield around the chromium basket. The current should be 6-9 A, do not turn it up too far or it high energy material will strip gold from the chamber walls, which may fall onto your substrate. After a few seconds glance at the substrate, it should have turned silver. Press "Stop".
15) Choose "Source A" and press "Enter".
16) Slowly turn the knob, keeping the current to about 3-4 A, until the arrow moves just past "12 o'clock". Leave for the allotted time to run out. It is possible to look at the gold basket through the filter of gold deposited on the walls. Ensure that all the gold is evaporated. If not run another evaporation cycle.
17) Press stop until venting message appears. Undo retaining nuts and remove blast shield. When it has finished venting open side door and remove substrate.
18) When it is no longer needed, reassemble and press "Start". Choose " Vacuum Shutdown Cycle". Follow instructions.
| |