Effect of Surface Roughness on the Sheet Resistance of CP Titanium Foils

Abstract

In this study, we investigated the effect of physical surface roughness on the sheet resistance (Rs) of commercially pure titanium (CP-Ti, Grades 1, 2, and 4) foils with varying impurity compositions. Microstructural observations revealed that the grain sizes of Grades 1 and 2 were 24 and 20 μm, respectively, whereas Grade 4 exhibited a very fine microstructure with indistinct grain boundaries. The surface roughness of the as-received CP-Ti foils was approximately 0.05–0.06 μm, showing no significant difference among the grades. However, the sheet resistance was determined to be 4.05, 4.60, and 4.82 mΩ/□, respectively, indicating an increase with higher impurity content. In contrast, when the surface roughness was mechanically controlled, the sheet resistance of all specimens increased with increasing surface roughness for all grades, confirming a linear correlation between surface roughness and sheet resistance.