Effect of ion energy and fluence on the electrical resistivity of silver implanted copper surface

Abstract

Oxygen-free high thermal conductivity copper (OFHC) is widely used in accelerator beamlines due to its properties like high electrical and thermal conductivity, high impact strength, and high ductility. However, due to thermal stress, the properties of copper degrade with time. Small quantities of controlled introduction of silver atoms in copper help alleviate this problem by reducing the thermal stress, without altering its conductivity properties. In this study, we characterize for the first time copper plates implanted with silver ions. Electrical resistivity measurements were performed to observe changes in the properties of copper implanted with Ag at various fluences. The 100 MeV Ag ions were implanted on thick copper plates, and 70 keV Ag ions were implanted on thin copper films deposited on Si and Sapphire substrates. Characterizations of the surface morphology and the chemical composition were performed on both pristine and implanted samples. While the Rutherford backscattering technique confirmed the presence of implanted Ag ions in Cu thin films, the Raman spectra showed the depth of ion implantations. Electrical resistivity tests performed on these samples showed a change in the sheet resistance after irradiation and annealing. In the irradiated samples, the decrease in the sheet resistance points out a mechanism associated with the presence of silver, even in a very low amount.