| Description |
Dynamic Tunneling Force Microscopy (DTFM) is an Atomic Force Microscopy (AFM) technique used for imaging and characterizing trap states on nonconducting surfaces. In this thesis, DTFM images are acquired under Kelvin Probe Force Microscopy (KPFM) feedback and height feedback control. Simultaneous acquisition of DTFM, surface potential, and topographic images is realized, and correlation between trap states, surface potential, and surface topography can be extracted. The methodology for obtaining three-dimensional location and energy of individual atomic scale electronic trap states is described. The energy and depth of states accessible by a DTFM experiment are calculated using tunneling and electrostatic models. The DTFM signal amplitude is derived using a one-dimensional electrostatic model. Comparison between simulated DTFM signal and experimental results show a good consistency, verifying the single electron tunneling model. DTFM is demonstrated on interlayer dielectric materials. Density, spatial distribution, energy, and depth distribution of trap states in these materials are measured by DTFM. An atomic scale study of electrical stressing effects using the DTFM method is performed showing both state appearance and disappearance after electrical stressing. |
