7 A New Approaches for Design of Ferroelectric Active and Passive Components Vahe Buniatyan 1 and Spartak Gevorgian 2 1 State Engineering University of Armenia, SEUA, 0009, Yerevan, RA 2 Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden 1. INTRODUCTION Ferroelectric ceramics and thin-film passive elements have long been used in microwave microelectronics as materials, ensuring high performance [1,2] . They are cur- rently used in various fields of microwave microelectron- ics [3] . In the recent years, the perspective of MOS transistors with ferroelectric gate in manufacturing of non- voltaic memory elements has raised the attention of researchers to these materials [4,5] . In addition intensive studies are conducted in improving performance and other dielectric properties(leakage current, the mechanisms of charge injection from the contacts, loss tangent, atomic – crystalline structure of ceramic and thin-film materials, electronic spectra, the mechanisms of fatigue and hystere- sis effects of thin-film structures) of ferroelectric micro- wave components [1,2,6-11] . Neverthless, the above-mentioned studies mainly have experimental character. In these experimental studies, there is purpose to detect and verify the injection properties of contacts, the probability of injection mechanisms, (SCL, Schottky, Tunnel, Fowler-Nordheim, Pool-Fraenkel, etc.), the presence of oxygen vacancies(as the inevitable defects in ferroelectric materials) and their effect on various prop- erties of ferroelectric materials [1,2,8,12-15] . However, there are relatively few studies in which the electro-physical causes of these injection current forma- tion, hysteresis effects in C-V, ε-V dependencies, the phe- nomenon of fatigue, as well as the connection between these phenomena with nonlinear dependence of dielectric permittivity of electric field, the concentration of deep “traps” level(due to oxygen vacancies and their energy distribution in the forbidden band), the phenomenon of charge carriers ionization due to Pool-Frenkel mechanism etc are theoretically accurately stated. 2. MODEL ISCRIPTION We offer new approaches to research, theoretical calcu- lations, as well as mathematical modeling of the above characteristics of ferroelectric microwave components, where there are taken into account: a) that the dielectric permittivity of ferroelectric materi- als is nonlinear dependence of applied electric field: , where and is the permittivity at zero bias. For example, for SrTiO 3 , β = 8 × 10 9 V·m 5 /C 3 , ε(0)=300 and A=0.45·10 -15 (m/V) 2[1,3,8] ; b) Some point defects(i.e. oxygen vacancies) are cre- ated energy levels for charge carriers in the gap of ferroe- lectrics: deep-level trapping states with energies in the range of W v +2.4 eV to W v +3.15 eV and a series of shal- lower traps near the conduction band edge in the range of W c -W t =0.06-0.4 eV. These electron traps are attributed to oxygen vacancy or iron transition-metal/oxygen vacancy defects. The point charge concentration ranges from 10 14 to 10 18 cm 3 in the as- grown films. Oxygen vacancies are the most common in perovskites. In agile microwave devices based on paraelectric phase ferroelectrics the oxygen vacancies cause high RF and DC leakages currents, microwave losses and distortion(hystere- sis) of C-V, tanδ-V , and I-V dependences [1,2] . In memory applications the oxygen vacancies cause fatigue [8] . Per- haps the point charge defects should be kept responsible for 1/f noise too. c) the high concentration of oxygen vacancy is “endowed” ferroelectric to n-type semiconductor proper- ε Er , ( ) ε 0 () 1 AE 2 + ( ) 1 – = A 3βε 0 ε 0 () [ ] 3 = ε 0 ()