Analysis of impedance spectroscopy data - Finding the best system function

Impedance spectroscopy gains much attention as a non-destructive analysis technique in many areas of materials science and device manufacturing. While it is relatively easy to collect data, the correct analysis or the data interpretation is not a straightforward task. In this paper, a novel analysis technique that provides a simple mean to identify the best system function is shown. A new taxonomy of all the possible circuit models that are based on RC lumped elements is given. The taxonomy divides the various circuit models into groups of increasing complexity. Its order and family, where for RC elements there are four different families, identify each group. A "black box", rather than a pre-assumed circuit model, represents the sample under test (SUT). The simplest group (order and family) that describes the SUT accurately within the experimental limitations can be found in a single experiment. In some cases, the best circuit model within the group can also be found by investigating the behavior of the SUT under various changes (i.e., temperature, radiation, other environmental conditions, sample construction, etc.). The technique is demonstrated on various circuits with lumped capacitors and resistors. This is done both on actual systems and on synthetic data with artificial noise. A comparison of this method with a standard Cole-Cole identification demonstrates the power of the new approach.