Question: We want to have a thin (~10 nm) conductive coating of carbon (graphite) on Si samples. While a C sputtering target is available in market, 

manufacturers don't spcify its (i.e., C) deposition rate and quality of the film (specially conductivity) after deposition via sputtering. 

Does anyone have any experience on C sputtering? Could you kindly enlight on that matter?

Valuable answer: 

The sputter deposition rate of carbon can be quite variable and depends on several factors, including the power supplied to the sputtering system, 

the pressure of the sputtering gas, the type of the sputtering gas, the distance between the target and the substrate, and the properties of the target itself.

Therefore, it's not surprising that manufacturers don't usually specify a deposition rate for their sputtering targets.

As a rough estimate, deposition rates for carbon can typically range from around 0.1 to 10 nm per minute under common sputtering conditions. 

Achieving higher rates with more aggressive sputtering conditions is possible, but these might result in poorer film quality.

The conductivity of the deposited carbon film can also be quite variable and will depend on factors such as the specific sputtering conditions 

and the structure of the deposited carbon. In general, the deposition conditions need to be carefully optimized to achieve a conductive film.

For example, lower pressure during sputtering (e.g., 1-5 mTorr) can result in more energetic sputtered particles and a denser, more conductive film. 

On the other hand, using a higher pressure can result in a less dense, more amorphous film with lower conductivity.

The sputtering gas can also have an impact on film properties. For carbon, argon is commonly used, but adding reactive gases like nitrogen or 

acetylene can help to control the film's structure and conductivity.

A sputtering system should undoubtedly make a 10 nm carbon coating feasible. Still, it will likely require careful optimization of the deposition 

conditions to achieve a conductive film of the right thickness. It's also worth noting that characterizing such a thin film can be pretty challenging 

and might require specialized techniques like X-ray reflectivity (XRR), atomic force microscopy (AFM), or ellipsometry.