KTa/sub 0.6/Nb/sub 0.4/O/sub 3/ ferroelectric thin film behavior at microwave frequencies for tunable applications

Abstract

In this study about the relationships between structural and microwave electrical properties of KTa1-xNbxO3 (KTN) ferroelectric materials, a KTN thin film was deposited on different substrates to investigate how KTN growth affects the microwave behavior. Interdigital capacitors and stubs were made on these films through a simple engraving process. Microwave measurements under a static electric field showed the importance of the substrate on the circuit behavior and, notably, on the tuning factor.

Control of composition and structure of ferroelectric oxide thin films grown by pulsed laser deposition

“…Various films of KTN with different compositions were integrated in microwaves devices. The high tunability measured on interdigited capacitors and stubs emphasizes the potentiality of these KTN films in view of reconfigurability of new devices for telecommunications [10,11,43].…”

“…We investigated two types of compounds: i) a bismuth layeredperovskite SrBi 2 Nb 2 O 9 (SBN) which is characterized by a high T c near 700 K [6] and is essentially developed for integration in FeRAM devices [7] ii) a perovskite-like oxide KTa 1-x Nb x O 3 (KTN) the T c of which can be monitored by the composition (x) [8,9]. We developed KTN thin films mainly in view of microwaves tunable devices [2,10]. Prior to integration of these materials in devices, crucial main steps reported in this paper are essential: the control of their composition and structure, i.e.…”

Epitaxially grown ferroelectric thin films for agile devices

“…Interdigited capacitors (IDC) and stub resonators, with gaps of 20 m for both devices, were designed using a combination of electromagnetic (Momentum) and circuit (Advanced Design System) simulations [36]; the design of the devices was optimized for a substrate permittivity of 10. A 4-mm thick gold layer was deposited by screen-printing on the ferroelectric film and annealed at a temperature limited to 750 C in order to reduce degradation of the film, while keeping a sufficient sintering of the Au layer.…”

“…These resonators were measured as detailed in [36] with a network analyzer and a probe station. The DC bias was applied via the probes and was then limited to 30 V to avoid damages to the latter.…”

Numerical study on dielectric permittivity for the ferroelectric ceramic with composition KTa0.6Nb0.4O3

“…KTa 0.6 Nb 0.4 O 3 compound is denser than other compositions and presents ferroelectric and piezo-electric characters at room temperature. In addition, the KTa 0.6 Nb 0.4 O 3 can be used in the fabrication of agile circuits [19]. * Corresponding author.…”