ABSTRACT
This chapter describes the assessment of electrical impedance based on measurement in time domain. The electrical impedance is useful for material characterization. Especially, process relevant material characterization requires fast but precise measurement. Electrical impedance measurement is a method for nondestructive and label-free characterization of any kind of material. Spectral information is useful for characterization of frequency dependent polarization behavior. Time domain– based measurements rely on digitization of the excitation and the response function which is basically compatible with modern electronics. Impedance measurements in reflection mode are not limited to high-frequency measurements but in most cases used for measurements above 500 MHz up to the 100 GHz. Impedance measurements and especially the transformation between time and frequency domain is limited to linear and time invariant materials. A feasible concept is the measurement of the response of a broad bandwidth signal in time domain and transformation of the answer into the frequency domain for calculation of the electrical impedance.
