Abstract
•We deposited Mo thin film by DC-sputtering for solar cell back contact application.•We examined the changes in the film quality in terms of structural, and electrical upon vacuum thermal annealing.•Vacuum thermal annealing at different temperature changes the degree of preferred orientation of (110) and (211) significantly.•Correlation of structural and electrical parameters was carried out.
In this study, the effects of vacuum annealing on the structural and electrical properties of DC-sputtered molybdenum (Mo) thin films have been investigated. Mo thin films were deposited by DC sputtering and subsequently subjected to vacuum annealing in a tube furnace from 350 to 500°C. Films that were deposited with different temperatures showed good adhesion with soda lime glass substrate after “tape testing”. X-ray diffraction (XRD) spectra have indicated existence of (110) and (211) orientations. However, I(110)/I(211) peak intensity ratio decreased for all vacuum annealed Mo films compared to as-sputtered films indicating change of preferential orientation. This suggests vacuum annealing can be employed to tailor the Mo thin film atomic packing density of the plane parallel to the substrate. SEM images of surface morphology clearly show compact and dense triangular like grains for as-sputtered film, while annealed films at 350°C, 400°C and 450°C indicate rice-like grains. Stony grains with less uniformity were detected for films annealed for 500°C. Meanwhile, electrical resistivity is insensitive to the vacuum annealing condition as all films showed more or less same resistivity in the range of 3×10−5–6×10−5Ωcm.