Thin Films

Thin films are an important basic element of microsystem design. They are used for masking in etching processes, as a diffusion stop layer, and as functional elements such as electrical conductors, membranes, and beams. Thin films may consist of nearly every rigid material. Typical examples are metals, polymers, oxides, and nitrides. The thickness of thin films typically is in the range of 50 nm – 10 μm. The lower limit is due to the problem that layers with an average thickness of less than 50 nm hardly are made homogeneously, because they tend to form separated clusters. The upper limit is a kind of convention. Films that are thicker than 10 μm are no longer considered to be thin in microtechnology, and they cannot be generated easily by processes such as sputtering and evaporation but need to be produced by, e.g., electroplating.