Since one the most important parameter of growth condition for thin films is surface roughness and it 's variations with deposition factors, [1,2,3] in this work aluminum thin films have been coated on glass substrates using magnetron sputtering technique.
To measure the roughness and study how it is related to deposition rate of Al and substrate temperature,investigation of surface by Atomic Force Microscopy(AFM) Were carried out. For varying of coating rate, discharge current was changed from 0.2 to 1.4 A, and Argon pressure range of 0.02 – 0.1 m bar was used, and Voltage due to these changes to varied from 230--450 volts.Deposition rate of 3 to 15 Å/s were obtained .Temperature of substrate was changed from 300 to 500˚K and measured by an exact digital thermocouple which was placed behind the stainless steel substrate holder.
Surface roughness of these produced sample of Al thin films rises when deposition rate is increased while thickness of Al films was same(≈100 nm),and substrate temperature also was kept constant(300˚K).Since coating rate is directly related to electrical power,[4],and increases by lowering gas pressure.higher speed or energy of sputtered Al atoms produce thin films with more roughness on surface and this can be important from adhesion point of view when another layer of film is going to be coated on Al thin film.
When substrate temperature has been increased, surface roughness of Al thin film also becomes more, but after certain amount of temperature roughness not only does not increase, but also starts to show a little decrease which this behavior can be due to change of Thornton's structural zone model,[5,6],structure function (s2(l)) as well as correlation length (l0) in this work also have been investigated for different deposition conditions.
References:
[1]. H.Savaloni,A.zendehnamand A.taherizadeh,Journal .Sci,277-282(2004)
[2]. A.Zendehanm,M.Khaneghaei and M.Mirzaei,Inter Conference on Nano Technology,Basel/Switzerland,(2006)
[3]. G.R.Jafari,S.M.Fazeli,F.Ghasemi and S.M.Vaezallaaei, Cond.Mat.Vol 118,(2005)
[5]. Thorenton J.A.J.vac.Sci.Technol.,12 :830(1975)
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