Preparation and Structural Investigation of Ultra-Uniform Mo Films on a Si/SiO2 Wafer by the Direct-Current Magnetron Sputtering Method

As a kind of important strategic resource, molybdenum (Mo) and its alloys are widely applied in solar cells and 5G radio frequency filters. In order to improve the yield of industrial production, it is important to reduce the nonuniformity of thin-film thickness. We prepared Mo films on CMOS compatible Si/SiO2 wafers through a magnetron sputtering method and systematically investigated the effect of tuning of several process parameters on film thickness nonuniformity and other structural properties, including crystallite size (D), microstrain (epsilon), and dislocation density (delta). At optimized sputtering power (80 W), chamber pressure (0.4 Pa), argon flow rate (90 sccm), substrate temperature (350 degrees C), and target-substrate distance (9 cm), the deposited 200 nm-thick Mo films show a unified < 110 > preferred orientation, and the film thickness nonuniformity reaches an excellent value of 0.46%, with a surface roughness of 0.83 nm and the full width at half maximum (FWHM) of X-ray diffraction (XRD) (110) rocking curve as low as 0.47 degrees. Our results provide efficient reference for the preparation of uniform metal films, which have potential for improving the quality and yield in filter device manufacturing.

Automated summary

This study prepared molybdenum (Mo) films on CMOS compatible Si/SiO2 wafers through a magnetron sputtering method and systematically investigated the effect of several process parameters on film thickness nonuniformity and other structural properties. The optimized process parameters resulted in films with unified <110> preferred orientation, excellent thickness nonuniformity of 0.46%, surface roughness of 0.83 nm, and low X-ray diffraction (110) rocking curve of 0.47 degrees. These results provide an efficient reference for the preparation of uniform metal films and improving the quality and yield in filter device manufacturing.