I will do the deposition of thin layers using a plasma gas mixture of argon and acetylene gas. with argon gas as a carrier gas and acetylene gas as a carbon source to be deposited. acetylene ionization energy is smaller than the ionization energy of argon. in this case, in order to generate the plasma and can be made thin layer deposition, ionization energy that is required to be above the ionization energy of acetylene or argon? thanks for your reply
In order to get your carbon for your deposition you have to dissociate the acetylene molecule. Depending on what happens first (ionisation or dissociation) you can compare that value or the sum ob both to the ionisation potential of Ar (in my opinion the latter should be lower).
Anyhow, usually you don't calculate the energy per particle but rather use the overall energy for creating the plasma but this depends on your kind of plasma source.
thanks for your reply sir. according to my understanding of your answer, in this case the argon gas may be ionized or not the most important thing is the acetylene gas must dissociate and ionized. did it really like that sir?
No, that's not what I am saying. The acetylene has to be dissociated to get the carbon out of it (depending on the kind of films you want to have, of course). Ar is mostly used precisely of its low ionisation potential and chemical inertness. So, the Argon gives you a higher number of free electrons which then dissociate/ionize your acetylene over inelastic collisions.
It would actually very beneficial, if you would give some more details about your experiment because then also the answer can be much more precise.
Yes sir. I understand. This experiment I have not done because of problems created a tool that I have not finished. maybe if I have done and I am still having trouble, I'll ask again. thank you
Hello, general practice is to generate Ar plasma and then add C2H2 in the plasma. Heavy Ar ions will then dissociate it and free C. You may also try to use N2 instead of Ar. The reason is momentum transfer between excited N2 and C2H2 is better than that of between Ar and C2H2. BTW, it is better if you say what type of plasma system you are using and what type of carbon material we want to synthesize ? If your aim is to deposit nano-carbon structure then proper ration of Ar: C2H2 is very important.
I would not use N2 because it chemically reacts especially with the hydrogen from your C2H2 - so it might alter the composition of your films tremendously.
Yes, Johannes is correct as N in plasma would form CN bands and also gets doped in the film but it turns out to be helpful in my case where I work with CNTs for field emission device and N creates favorable bamboo-like defects in the structure and it also increases deposition rate. That's why I asked for "type of carbon material" .
Mr. Rajib Kar.
Type of plasma system that I'm using is CVD plasma. And, carbon that will deposite is DLC film type. I'm using Ar gas, because it only as carrier gas not to react with the C2H2.
But because some problems that I have my experiment no longer use acetylene gas but using blue gaz as source of carbon.
Mr. Rajib Kar.
yes sir. But because some problems that I have my experiment no longer use acetylene gas but using blue gaz as source of carbon for now.
Hello Mira, It depend on the type of carbon layers that you want to deposit.
In any case, if you use argon/acetylene mixture, you probably synthetize dust particles during the process which can contaminates your wafer.
- Badges
- Science topic
- Similar topics
- Social Psychology
- Attitude