Electrical model of a thin dielectric film with a bottom electrode of non-negligible distributed resistance

• Published in: Ferroelectrics Vol. 497; no. 1; pp. 114 - 125
• Main Authors: Mackevičiūtė, R., Ivanov, M., Bagdzevičius, Š., Grigalaitis, R., Banys, J.
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 20.06.2016; Taylor & Francis Ltd
• Subjects: Algorithms; complex impedance; Dielectric constant; Dielectrics; distributed resistance; Electrodes; Ferroelectric materials; heterostructure; Mathematical models; Permittivity; Thin film; Thin films
• ISSN: 0015-0193; 1563-5112
• DOI: 10.1080/00150193.2016.1165023

Thin films are appealing objects of scientific studies due to attractive functionalities and novel physical phenomena. However, choice of the lower electrode (which is between the film and the substrate) is often limited for various reasons, and it might not be suitable for radiofrequency investigations of the film due to comparable impedances of the film and the contact. This paper presents a new theoretical model for complex heterostucture, which could describe impedance fairly well and would allow extracting dielectric permittivity of the functional ferroelectric layer even in the case of distributed resistance of the bottom electrode. The effectiveness of the presented theoretical model was proved by approximation of experimental data. The model has several disadvantages, such as complexity, suitability for linear systems only, potential failure in presence of electric DC bias. Despite the drawbacks, the model describes the experimental data in a physically proper way, unlike equivalent circuit model. Furthermore, an algorithm to find static resistivity and dielectric permittivity of the film in a simple way is also proposed.