- E-beam evaporates materials with a 4 pocket hearth
- Pockets hold 3.7 cc crucible liners
- Substrate fixture can hold four 5" wafers with rotation
- uses a Telemark 860 deposition controller to monitor deposition thickness
- uses a load lock vacuum system.
Organic substrates allowed
Source Materials: Au, Pt, Ti, Cr, Cu, SiO2, Al2O3, Al, Si, Ni, NiCr, Ag, Pd
Standard Operating Procedure
Please Note: This instrument is billed per use based on a 4 hour block
Example : 1 user only uses the tool per use. When you vent the system and unload your sample that concludes your reservation .
Example: If the usage is 10+ minutes past the initial 4 hour reservation, you will be billed for 2 uses
Questions & Troubleshooting
1.Why are we limited to only 500 nanometer thickness per material ?
Answer: Due to the small crucible size we have to limit depositions to keep from burning through the hearth assembly
2 Why does pump down take so long?
Answer: Due to the use of organic materials that coat the cryo and system componets it takes longer for the vacuum system to pump all of the out-gassing from the organics
I had a problem with the way the last aluminum samples turned out. It looked like there were almost pin holes or something in the aluminum layer. I am not sure if you know what may have been wrong but I can show you the samples and maybe you have an idea of what caused it.
The pinholes are most likely caused by contaminates on the substrate , below are some more comments
Dear Dr. Sivagami
Deposit the film at higher vacuum than what you are using at present. For good adhesion, Degass the substrates before deposition. Make slightly thicker films. Anneal them after evaporation in vacuum at higher temperatures for getting rid of voids. See if you are able to solve the problem. Substrate cleaning can also be improved for better uniformity. Good luck.
If substrates are glass plates, degassing is done by putting a heater inside the coating unit over the substrates and heat them up to 200 degree centigrade for about two hours in vacuum. The gasses absorbed comes out in this process. Switch off the heater to cool down to room temperature. Thereafter, deposit the film without exposing them to air.
Added an answer
pinholes are mainly created due to any foreign material already present in the substrate and they tries to come out through the deposited films during deposition. Clean your substrate thoroughly in piranha solution (1:1 ratio of H2O2 and H2SO4 for 20 min. ** you can search in net for details) . Thereafter rinse in DI water and preheat in oven @ 150 deg. Cent. for at least 30 min and then place in thermal chamber for deposition. Also you should heat your substrate up to 150 deg. cent. just before deposition. For better film quality high vacuum is essenti
Pinholes are either caused by surface contamination remaining on the "cleaned" surface. Use the water break test to determine if the surface is residue free. You will see interference fringes as it dries. The fringes will be even as the water evaporates. Any island fringes or streaks means the surface is not clean. Any of these particles actually become nucleation sites as the coating is deposited