As we have seen, the chemical vapor deposition process has a profound influence on the physical and especially the optical properties of CVDZnS. The scalability of this process was certainly a determining factor in the rapid displacement of the hot-pressed process initially used to commercially produce ZnS (IRTRAN 2). For this reason, a review of the development of the CVD process, first as an industrial process and finally as it was applied to ZnS, is in order.
This chapter recounts the events leading up to and including the
development of the commercial ZnS CVD process. As Angus Macleod aptly points out in his description of the early days of optical coatings,1 technology rarely evolves in a systematic way, being “very disorganized.” Technological advancement only takes place when the climate is favorable, including the right time and place (and the individuals with the required skills are engaged), and importantly when the “subject,” as Macleod calls, it is ready to receive it. Macleod argues that of these factors, climate is most important. In this sense, the climate at Raytheon Company in the 1960s was ideally suited for the development of CVD ZnS.
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