SilcoTek’s amorphous silicon-based coatings applied by chemical vapor deposition (CVD) are trusted and relied upon by some of the world’s largest companies in high-purity industries such as semiconductor manufacturing, biopharmaceuticals, and medical devices. Our coatings provide significant cost savings by extending product lifetime and maintaining an inert barrier on stainless steel, allowing customers to move away from expensive exotic alloys with long lead times. Still, for some high-purity applications like semiconductor manufacturing where a single foreign particle can cause costly process failures, it is important for us to explain potential byproducts from the CVD coating process, their implications, and how SilcoTek helps customers overcome them.
Most of our coatings contain silicon and carbon with a small amount of oxygen (mostly from oxide layers on the surface). We functionalize the surface for specific inertness performance but our Silcolloy coating and SilcoNert 1000 coatings are made of silicon with a native oxide surface only. Non-reactive silicon makes an excellent barrier which prevents contamination from the base metal, glass, or ceramic surface. The Auger Electron Spectroscopy (AES) diagram below of a SilcoNert® surface shows the coating contains silicon and oxygen. Note the diffusion zone where the silicon is bonded to the stainless steel base.
Dursan® is a different coating consisting of silicon, oxygen and carbon. The Auger plot below shows the coating depth and a similar diffusion zone to SilcoNert.
Each coating's composition can be found on their data sheets.
There are two byproducts from our coating process: water and sand. Silicon coatings produce minimal emissions and outgassing, but the process can result in the presence of silicon particles, sometimes referred to as silicon dust or sand. These particles may form during manufacturing or remain on the surface after processing, despite our efforts to minimize them.
While silicon is an inert and non-reactive material, particulate contamination can be a concern in ultra-high purity environments where even trace contaminants must be controlled.
For applications requiring the highest cleanliness standards, particulate testing is recommended to determine if any residual silicon particles are present on coated parts. If additional cleaning is needed, SilcoTek offers ISO Class 6 cleanroom services, and third-party vendors specializing in cleanroom-grade cleaning can be utilized for larger parts to further refine surfaces to meet strict requirements.
SilcoTek's in-house cleanroom offers:
Industries such as semiconductor manufacturing and optics depend on precise contamination control. Understanding potential coating byproducts and taking appropriate measures—such as testing and additional cleaning—can help ensure that coated parts meet the necessary purity standards.
For further guidance on mitigating silicon particle contamination, discuss your application with your SilcoTek sales representative or a third-party cleaning vendor specializing in ultra-high purity applications.
Contact us for more information on our process or to discuss our cleaning techniques and services.