Microelectronic materials and structures characterization by impedance spectroscopy

摘要

The impedance spectroscopy relies on the measurement of a linear electrical response of an investigated material to a low electromagnetic signal in a wide range of frequency. Further analysis of this response is applied to reveal some information about physicochemical properties of the material. Impedance spectroscopy is a useful, non-destructive tool for the analysis of many material properties. It is also commonly applied for the determination of the electrical parameters of complex electronic and microelectronic structures. This kind of knowledge enables better understanding of the mechanisms of operation of the microelectronic devices under investigation. Fundamental issues are discussed, including the proper interpretation of the experimental results and the construction of the equivalent circuits, which shall consist of the elements representing the impact of the particular mechanisms of electrical conductivity and polarization on the electrical parameters eventually observed in macroscale. The considerations are illustrated by results of the author's research on thin and thick film structures and materials. Some examples of the impedances spectra analysis and the construction of the equivalent models are presented for various structures, including the, metal-SiO_2-GaAs, metal-TiVPd-Si and thick film humidity and gas sensors.