A thin film preparation using focused high power ion beam

Abstract

Among the well known physical methods of thin film preparation such as target evaporation by magnetron irradiation, by laser, electron and long pulse ion beams, the method of precipitation of evaporated target material with short pulse ( 10/sup 9/ /cm/sup 2/) ion beams seems to be less investigated. The advantages of such method are: 1. high precipitation velocity (/spl sim/1 /spl mu/m per shot); 2. possibility of film formation over high area substrate (/spl sime/100 cm/sup 2/); 3. moderate vacuum conditions needed (10/sup -4/-10/sup -5/ Torr) two orders higher compared to other methods; and 4. high melting temperature target usage. These advantages are provided by the action of a pulsed ion beam at the target, when the effective energy transfer into target occurs, but irradiation energy losses are minimal. The thickness of the evaporated layer of the target is determined by the ion range in material (usually 1-10 /spl mu/m) providing high velocity precipitation. The pulsed action of the target plasma results in thermal and mechanical dynamic loading, that is important for film properties. The usage of described method for formation of diamond like material is of the most interest. In order to precipitate the carbon films we used high power ion beam with the following parameters: E/sub i/=600 keV, I/sub i/=60 kA, /spl tau/=80 ns. Ion beam was generated in focusing B-applied diode at GIMN accelerator. The ion beam consisted of approximately 70% of protons and 30% of carbon ions. The ion current density in the focal plane reached 9 kA/cm/sup 2/ that corresponds to 300 J/cm/sup 2/. The low impurity carbon target (5/spl times/5 cm) was placed at the diode axis with angle of 90/spl deg/ from focal plane. In the report the elliptsometric data obtained with scanning electron microscope are given.