For instance, the addition of oxygen during plasma deposition may result in a smooth and dense film. I am curious not only about the density, but any other possible morphological differences between the films deposited with and without a presence of a gas during plasma treatment.
Thank you in advance for the response.
Hi
Are you referring to any particular type of plasma (DC, RF, MW...)? The gas pressure in principle cannot changed arbitrarily without affecting the plasma stability. If you mean adding reactive species (like oxygen, hydrogen, nitrogen...), the resulting effect on film properties is mostly due to the associated plasma chemistry...( i.e., etching of loosely bond adatoms..)
Dear Francisco
Thank you for your answer, I refer to the addition of reactive species during low pressure glow discharge plasma treatment (at any frequency of the power source). And I wanted to find out the possible influence of each type of gas on final film properties.
For examples, Yuan et al. demonstrated that the addition of oxygen during plasma deposition resulted in more smooth and dense films (the link is provided)
Kind regards
Dan
The variation in the density of thin films is more related to pressure, rather than the gas. Lower pressures can provide better/higher density, whereas higher pressures, resulting in more collisions of the ejected target specie can result in deposition at random/oblique angles, in which case the film can develop a much more porous micro-structure.
You can refer to the classic book by Rf Bunshah in which they discuss the commonly well known Thornton diagram explaining the effect of substrate temperature, and pressure on the final microstructure of the deposited films.
K. Sreenivas
Dear Professor Sreenivas
Thank you for your answer!
I am aware of the importance of low pressure system and consequently deposited films of a high density. Although, I am still interested in the influence of reactive species :) Imagine we already talk about a plasma treatment system with turbo molecular pumps, so low pressure is not a problem, what would be the case in terms of using different gases in this situation?
Kind regards
Dan
High density of film also depend on substrate temperature.Partial pressure ratio of Argon and oxygen should be 2:1. Chamber pressure should be reduced to lower pressure and then sputtering gas is introduced up to optimize pressure.
Dear Shailaj Kumar
What is the exact justification of this ratio for the gases which should be introduced to a vacuum chamber?
Kind regards
Dan
Partial pressure ratio of Argon and oxygen may also be 3:2 or 2:1.Oxygen is generally used to restore the oxygen content in the material like YBCO(123) during deposition.Argon is suitable as it is non-reactive with the composition of the target.
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