The Buffer Gas Influence Rate on Absolute Cu Atoms Density with regard to Deposition

The absolute Cu atoms density in Cu(2S1/2ÔåÉ2P1/2) ground state has been measured by Resonance Optical Absorption (ROA) technique in a DC magnetron sputtering deposition with argon. We measured these densities under variety of operation conditions: pressure from 0.6 μbar to 14 μbar, input power from 10W to 200W and N2 mixture from 0% to 100%. For measuring the gas temperature, we used the simulation of N2 rotational spectra with a special computer code. The absolute number density of Cu atoms decreases with increasing the N2 percentage of buffer gas at any conditions of this work. But the deposition rate, is not decreased with the same manner. The deposition rate variation is very small and in the limit of quartz balance measuring equipment accuracy. So we conclude that decrease in the absolute number density of Cu atoms in magnetron plasma has not a big effect on deposition rate, because the diffusion of Cu atoms to the chamber volume and deviation of Cu atoms from direct path (towards the substrate) decreases with increasing of N2 percentage of buffer gas. This is because of the lower mass of N2 atoms compared to the argon ones.

Authors:

• S. Sobhanian
• H. Naghshara
• N. Sadeghi
• S. Khorram

Keywords:

• Deposition rate
• Resonance Optical Absorption
• Sputtering.

References:

[1] Lin Xu, N. Sadeghi and et.al., J. of Appl. Phys. 101, 013304
(2007).
[2] J.Tenenbaum and et.al., Optics Com. 32, 473 (1980).
[3] A.C.G. Mitchell, M. W. Zemansky, 1971, " Resonance
Radiation and Excited Atoms " , Cambridge University Press,
London.
[4] S.Konstantinids and et.al., J. of Appl. Phys. 95, 2900 (2004).
[5] E. Eslami and N. Sadeghi, J. of Appl. Phys. 43,93-102 (2008).
[6] P. Baltayan, F. Hartmann, I. Hikmet and N. Sadeghi, J. of
Chem. Phys. 97, 5417 (1992).
[7] H. Naghshara, S. Sobhanian, S. Khorram and N. Sadeghi. Phys.
D: Appl. Phys. 43, (2010) under publication.