Investigation of Cu films by focused ion beam induced deposition using nuclear microprobe

The localized Cu deposition on Si by 30 keV Ga+ focused ion beam (FIB) using precursor gas has been investigated by a 300 keV Be2+ nuclear microprobe with a beam spot diameter of 80 nm. The Cu deposition and impurity incorporation were compared at different temperatures of precursor gas. The distribution of deposited Cu, Ga from the ion beam itself and low-Z elements from the precursor gas was obtained at and nearby the deposited areas by RBS mapping images. An RBS mapping image of Cu atoms for FIB induced deposition indicated the uniform Cu films in the case of lower temperature (25 degrees C and 37 degrees C) of precursor. On the contrary in the case of higher temperature (43 degrees C and 50 degrees C) of precursor gas, the RBS mapping image of Cu atoms shows irregular distribution and incorporated impurities. The micro-RBS spectra indicated the deposition behavior that the thickness of Cu layers increased with the decrease in temperature of precursor gas due to the enhancement in the adsorption of precursor gas on the target surface.