PVD vs CVD

PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) are two techniques that are used to create a very thin layer of material into a substrate; commonly referred to as thin films. They are used largely in the production of semiconductors where very thin layers of n-type and p-type materials create the necessary junctions. The main difference between PVD and CVD is the processes they employ.  As you may have already deduced from the names, PVD only uses physical forces to deposit the layer while CVD uses chemical processes.

In PVD, a pure source material is gasified via evaporation, the application of high power electricity, laser ablation, and a few other techniques. The gasified material will then condense on the substrate material to create the desired layer. There are no chemical reactions that take place in the entire process.

In CVD, the source material is actually not pure as it is mixed with a volatile precursor that acts as a carrier. The mixture is injected into the chamber that contains the substrate and is then deposited into it. When the mixture is already adhered to the substrate, the precursor eventually decomposes and leaves the desired layer of the source material in the substrate. The byproduct is then removed from the chamber via gas flow. The process of decomposition can be assisted or accelerated via the use of heat, plasma, or other processes.

Whether it is via CVD or via PVD, the end result is basically the same as they both create a very thin layer of material depending on the desired thickness. CVD and PVD are very broad techniques with a number of more specific techniques under them. The actual processes may be different but the goal is the same. Some techniques may be better in certain applications than others because of cost, ease, and a variety of other reasons; thus they are preferred in that area.

Summary:

1. PVD uses physical processes only while CVD primarily uses chemical processes
2. PVD typically uses a pure source material while CVD uses a mixed source material

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