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Advanced electronics, energy storage and harvesting, etc. applications employ devices combining nano-thick layers of dielectric, semiconductor and metal materials. Electrical characteristics of such highly-scaled materials stacks are found to be strongly influenced by the charge transfer across the layers. Charge transfer processes are controlled, to a great degree, by the interface regions, their structure and composition being modified by the inter-materials interaction affected by stack fabrication conditions. These complex systems pose new challenges for analyzing charge transfer processes, which are sensitive to even extremely small concentrations of electrically active defects. In order to identify these defects, the critical task is to link the atomic-level structural features of multicomponent ultra-thin material stacks to their electrical characteristics affected by charge transfer.
We focus on analyzing oxide structural features responsible for the charge transfer by combining a variety of electrical measurement techniques with high time and spatial resolutions that allow capturing fast transient charging processes and differentiating signals from different regions through the depth of the multi-layer stacks. These data are used to fit the results of simulations of the physical processes underlying the electrical measurements in order to extract spatial and energy profiles of electrically active centers. The extracted characteristics are, in turn, compared to the atomic-level material modeling data to pinpoint atomic and energy material characteristics responsible for the electrical properties, thus, providing a helpful feedback to optimize the device fabrication process. We discuss examples of implementations of this approach for analysis and optimization of a variety of ultra-thin layers devices.
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