Electrical Properties and Microstructure of Chromium Thin Films Produced by Glancing Angle Deposition

Chromium (Cr) thin films were prepared on a silicon-wafer substrate using magnetron sputtering and application of the glancing angle deposition (GLAD) technique. The thickness of the thin films was controlled to be approximately 1 μm. Electrical properties were measured using a four-point probe method, and X-ray reflectivity (XRR) was used to measure the density of the films. High thickness uniformity and column angle in the Cr thin films were achieved by magnetron sputtering using the GLAD technique. The sheet resistance and column angle increased commensurate with increasing glancing angle; however, nanohardness and density decreased as the glancing angle increased. The measured density of the Cr thin films decreased from 6.1 to 3.8 g/cc as the glancing angle increased from 0° to 90°. The low density of Cr thin films results from the isolated columnar structure of the samples. The evolution of the isolated columnar structure is enhanced at low sputter pressures and high glancing angles. The GLAD technique can potentially be applied to the synthesis of thin films that require porous and uniform coatings, such as thin film catalysts and gas sensors.