BST NON-LINEAR DEVICES

This project titled" Non-Linear Device Applications of Nano-Patterned Barium Strontium Titanate Thin Films" is supported by the National Science Foundation under Grant No. 0601536.".

Disclaimer: Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation
 

The objectives of this work are to study the non-linear properties of barium strontium titanate (BST) thin-films and exploit their use in novel, miniaturized microwave-frequency devices. significant uses of BST are for dynamic random access memory (DRAM) and variable reactance devices (varactors)for microwave electronics, wherein a (DC) bias level is used to set the operating state and the BST behavior is nominally linear. To the best of our knowledge, the intrinsic non-linearity of the films has yet to be applied as a primary characteristic in device design.

    Ongoing work intends to investigate the feasibility of using BST to produce highly non-linear, practical RF devices and focus on the development of variants of non linear transmission lines (NLTLs). Conventional NLTLs are comprised of diode-loaded transmission lines and have proven to be effective as frequency multipliers and for pulse compression. Similar topologies are proposed herein, in which the semiconductor diode is replaced by a planar BST varactor, fabricated with a nano-scale patterning method such that high field strength is imparted to the thin film by a microwave signal. For the purpose of rapid prototyping, patterning of feature sizes on the order of 10 nm will be performed using focused ion beam milling. The NLTLs will be used in the design of frequency multipliers, modulators, and non-linear antennas.

Picture of the proposed BST Varactor implemented through a Nano cut (~ 10 nm wide) using Focused Ion Beam Milling

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RF Microsystems Group

A part of the Center for Wireless and Microwave and Information Systems, USF