Deposition Processes using Cold Cathode Broad Beam Ion Source

A modified broad beam ion source with a high output ion beam current has been locally designed and constructed and the performance of the broad beam ion source was modified by applying a negative extraction voltage on the extractor electrode. Also, the effect of applied negative extraction voltage on the output ion beam current was measured. Some investigations of this ion source have been done to come with its specification up to the required objects. This ion source has a compact size and is featured by easy and long stable operation using argon, oxygen and nitrogen gases. A stable discharge current could be obtained with maximum output ion beam current. This ion source can be used for surface modification, sputtering, deposition and different applications. The output ion beam current increases by increasing the negative extraction voltage and it is reaches more than 100 % its initial values at V_ext =- 600 volt and I_d=1.3 m A using argon gas. The ion source efficiency was obtained without and with applied the negative extraction voltage and it is reaches 28 % at P =2×10^-4 mmHg using argon gas at V_ext=-500 volt. The argon ion beam at conditions, extracted output ion beam current I_b = 800 µA, pressure 2×10^-4 mbar and energy 5 keV was used for prepared AZ31 samples. A low energy ion beam was used for treated polycarbonate samples for improvement the physical properties of the base polymer with various argon ion beam fluence 0.5x10¹⁸ ions.cm^-2 and 1× 10¹⁸ ions.cm^-2 at energy 5 keV. It can be seen that the direct and indirect energy band gap decreases with increasing ion fluence and the number of carbon atoms in clusters increases with increasing ions fluence it is also observed that the conductivity increases by increasing irradiation fluence. The irradiated polycarbonate with argon ion beam fluence 1×10¹⁸ cm^-2 was thermally stable up to 446 °C and then there was a great loss in weight of the sample up to 580°C and the glass transition temperature increases with increasing ion beam fluence. The tensile strength of PC increased from 9.36 for pristine to 14.6 MPa for irradiated sample using argon ion fluence 1x10¹⁸ cm^-2 Aluminum coating on AZ31 magnesium alloy using argon ion beam I_b=800 µA, at ion energy is 5 keV, pressure is 2x10^-4 mbar and time deposition 10 hour and the sputtering yield of aluminum was found to be 2.19 atoms/ion or 25 eV/atom at surface binding energy=3.4 eV. From XRD curve of AZ31, two peaks of Al coating are clearly observed, which are corresponded to the planes (111) and (200), respectively. The simulation program (SRIM/TRIM) used to calculate the sputtering yield of copper was found to be 6.87 atoms/ion and the copper film that was formed grow with a preferred orientation for various deposition times, yielding a strong (111) diffraction peak. It was found that the optical energy band gap decreased from 3.45 eV for the pristine PC sample to 1.7 eV for copper thin film.