Effect of substrate bias voltage on the texture and microstructure of Cu thin films deposited by ion beam deposition

Cu thin films deposited by non-mass separated ion beam deposition under various substrate bias voltages were investigated. The film textures and microstructure were analyzed by X-ray diffraction and field emission scanning electron microscopy, and the resistivity of the film was measured with the Van der Pauw method. It was found that the optimum negative substrate bias voltage for Cu films was −50 V. The Cu films deposited without substrate bias voltage showed a columnar grain structure with small grains and random orientation. However, when a substrate bias voltage of −50 V was applied, the Cu films had a non-columnar structure with a strong (111) texture and large grains. The electrical resistivity of the Cu films decreased remarkably with increasing negative substrate bias voltage, and reaching a minimum value of 1.8±0.13 μΩ cm at the substrate bias voltage of −50V.