# COMSOL_Predeposition or Carburation

1. Jul 14, 2009

### Rafa

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Hi,
I'm a beginer with COMSOL. I work in diffusion process and I's been trying to simulate with COMSOL a very simple problem, that i know solve mathematicaly.
I dont get the solution using COMSOL.
The problem is simulate a carburation or Predeposition process. Exemple; I introduce in a furnace a Si sample (1000ºC) The atmosphere in the furnace is rich in P because I want to deposite P in the surface of Si sample for a hour. I know that maximun concetration of P in Si is 1021 at/cm^3.

Mathemathically I know that I will get a 42 10-6 cm layer of P in Si sample but i dont know how introduce the boundary condition for flux in COMSOL. COMSOL need a flux=No+k(cb-c) for introduce a flux, but I don`t know how trasladate my data to the comsol

sorry for my english (i'm from spain). Could anybody help me?
I had changed this post from Physics Forum
thanks