Page "Amorphous solid" Paragraph 5

Amorphous phases are important constituents of thin films, which are solid layers of a few nm to some tens of µm thickness deposited upon an underlying substrate.

So-called structure zone models were developed to describe the micro structure and ceramics of thin films as a function of the homologous temperature T < sub > h </ sub > that is the ratio of deposition temperature over melting temperature.

According to these models, a necessary ( but not sufficient ) condition for the occurrence of amorphous phases is that T < sub > h </ sub > has to be smaller than 0. 3, that is the deposition temperature must be below 30 % of the melting temperature.

For higher values, the surface diffusion of deposited atomic species would allow for the formation of crystallites with long range atomic order.