Publications Details
Grain Boundary Diffusion Characterized by KPFM
The nanometer scale characterization technique of Frequency Modulated Kelvin Probe Force Microscopy (FM-KPFM) will be used to assess a preliminary diffusion study on thin metal films that undergo accelerated aging. The KPFM technique provides a relatively easy, non-destructive methodology that does not require high-vacuum facilities to obtain nanometer spatial resolution of surface chemistry changes and will be exercised in an effort to explore its capacity to map surface potential contrast caused by Cu diffusion in a manner that allows for a qualitative assessment of diffusion rate kinetics. Supporting data will be obtained from traditional techniques: AES, XPS and UPS. An aging study was conducted on thin metal test specimens comprised of Ti or Cr/Cu/Au layer thicknesses of 50nm/500nm/500nm up to 4μm respectively. The accelerated aging process, was performed in air at aging temperatures of 60°C, 100°C, and 125°C for aging times of 8 hours, 24 hours, 96 hours (4 days), and 216 hours (9 days). A calibration method was developed using Au, Al and Ni standards to establish precision and repeatability of the KPFM technique. Average CPDs and standard deviations for each metal were found and summarized.