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minger

Science Advisor

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**Theoretical Deposition Rate based on RPM -- Help ARRGGG!**

Hey guys, what's going on. I have recently started doing research for a professor here in the field of nanotechnology. It turns out that it's not all small robots and stuff. Right now I'm working with thin film coatings. ANYWAYS, we are using Ion Sputtering as our method of deposition right now. The prof just asked me to do this big experimented, and part of it involves heating the substrate. Now the way the machine works is that is first takes pressure in the chamber down to around 5x10^-7 torr, then we start. If we want to heat the piece, we have to rotate it. It rotates under the ion heater, then under the targer which coats it, then continues to rotate around.

ANYWAYS, he wants to know what the optimal rpm is to maximize coating. So, let's say we have an even just flux of whatever coming down into a circular area. You have another circular area rotating around underneath it. See the attached diagram for a better explanation. I just have no idea where to start. The deposition is a certain nanometers per meter squared per second.

I guess another way to think of it is if you have a large flow of water (say a waterfall). Then you have a large bucket that rotates underneath of it. What is the optimal rpm which to fill the bucket up the fastest.

Thanks a lot for the help if any. I'm thinking the final solution will be rather simple. Something in terms of radius and areas and rpm of course. I think getting there will involve some complicated integrals though.