Discussion Forum

Hi, I am new to COMSOL and I need some help simulating a physical vapour deposition. The goal is to enventually make something similar to an MBE growth chamber but for now I have a toy model with just a 1/4 3" wafer above an evaporation surface. I am using the Free Molecular Flow (FMF) module and I have managed to create a surface plot of the deposited film thickness. Here's the problem: if I am going to make this like an MBE chamber with multiple sources of different species all pointed at the center of the wafer I need to be able to rotate the wafer so that I can get a uniform deposition. I have spent many hours trying to solve this problem myself using the deformed mesh options to create a rotating domain or rotating boundary to simulate the wafer rotating. It seems like the FMF module is incompatible with a system with two seperate domains so I think the way to go is to just deform the mesh by creating a rotating boundary and then using automatic remeshing to restore the mesh once it has been too deformed, but this is extremely computationally intense and also causes different errors. The most common error I get is "Failed to find consistent initial values." which I know has something to do with the precision of the simulation but I'm not sure how to fix it. I would really appreciate it if anyone had some advice on how to include rotation in this simulation. I will attach my current file for reference.

P.S. The evaporating source is off-center on purpose to emphasize the effects of rotating the substrate.