I am interested in the response of a porous dielectric such as carbon-doped oxide to a large electric field. I was planning to first approach this like a homework problem. However, I am not sure if the pore in such material is actually empty or contains leftover gas or if it contains a different stoichiometry. The electric field should be concentrated in areas of lowest permittivity (dielectric constant), and may cause electron emission. Just don't know if anyone working with low-k can confirm if these pores are pure vacuum or pure gas or something else.

Thanks in advance

I don't know, but I doubt greatly that they are vacuum. I'd assume air after some period of time.

But, I wonder how much difference it will make in your results? Try it both ways and see.

Thanks Big Guy, I agree between air and vacuum, it shouldn't make a difference as far as calculating the electric field. I would take the dielectric constant for either to be 1. It may make a difference if the field enhances thermionic emission of electrons (schottky emission). In this case the inevitable presence of some gas (air or leftover hydrocarbons) in the pore would complicate the breakdown dynamics.