Selection Criteria for Chemical Vapour Deposition Precursors

1 Selection Criteria for Chemical Vapour Deposition Precursors 

For the deposition of a given material, there are generally a number of precursors available. The selection criteria of a suitable chemical precursor for coating applications are as follows [7, 8,18]  

The vapour pressure of the precursors must be high enough for the reasonable growth rates of the deposit. In order to prevent the vaporised gas from condensing in the delivery pipelines, the vaporising temperature should be set to a relatively low temperature, particularly lower than the deposition temperature. 

Whilst the precursors are required to be reactive at high temperatures, they should be stable enough to be carried into the reactor chamber, and no chemical reactions should take place below the deposition temperature. 

Precursor cost determines not only the cost of a precursor gas itself, but also the deposition efficiency and its environmental related costs. The above overall costs should be considered in the context of the precursor cost. Compared with the hydrides and halides, the metal-organic precursors are much more expensive. 

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