Influence of Substrate Bias Voltage on the Properties of Cu Thin Films by Sputter Type Ion Beam Deposition

Cu thin films have been deposited on Si (100) substrate by using a non-mass-separated ion beam deposition (IBD) system. The effect of the substrate bias voltage on the properties of the deposited films was investigated using X-ray diffraction, resistivity measurement and field emission scanning electron microscopy. In the case of Cu thin films deposited without bias voltage, a columnar structure and small grains were observed distinctly, and the electrical resistivity of the deposited Cu films was very high. By increasing the bias voltage, no clear columnar structure and grain boundary were observed. The resistivity of Cu films decreased remarkably and at a bias voltage of −50 V, reaching a minimum value of 18±1 nΩm, which is close to that of the bulk phase (16.7 nΩm.)