A comparative study of copper thin films deposited using magnetron sputtering and supercritical fluid deposition techniques

A comparison of crystallinity, microstructure, surface morphology and electrical conductivity is proposed for the deposition of copper films, using supercritical fluid chemical deposition (SFCD) and RF magnetron sputtering techniques. Both preparation methods yield nanocrystalline Cu films (< 100 nm) but SFCD gives access to a higher crystallinity for the same AlN substrate temperature during the deposit. Based on the film characteristics, a comparison of the evolution of electrical properties is done for RF magnetron sputtered copper films and SFCD ones with H2 as reducing agent. Uniform strain values are significantly reduced when SFCD technique is used and crystallinity is highly increased leading to lower resistivity values for a same crystallite size. This study demonstrates the viability of the SFCD technique to produce high quality nanostructured copper thin films with low resistivity values.