Effect of bias on amorph film structure

Thanks to SiMPore’s push for TEM grids, we’ve produced a lot of amorphous material in the last month under different deposition conditions.  Below I’ve illustrated the different film structures resulting from depositing with and without substrate bias and heating.

Without bias, the amorphous film exhibits clusters of thicker/denser? material (darker spots).  Intuitively, this makes sense since without the extra energy from the rf bias the adatoms do not have enough mobility to travel on the surface and simply “stick” to where they have been deposited.

This difference in structure between the bias/no bias condition can be seen in the nanocrystalline analogue, as noted here.