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ZrO2 Layer Thickness Dependent Electrical and Dielectric Properties of BST/ZrO2/BST Multilayer Thin Films Santosh K. Sahoo1,2, D. Misra2, D. C. Agrawal3, and Y. N. Mohapatra3 1

National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401, USA

2

Department of Electrical and Computer Engineering, NJIT, Newark, New Jersey 07102, USA

3

Materials Science Programme, IIT Kanpur, Kanpur 208016, India

ABSTRACT Recently, high K materials play an important role in microelectronic devices such as capacitors, memory devices, and microwave devices. Now a days ferroelectric barium strontium titanate [BaxSr1-xTiO3, (BST)] thin film is being actively investigated for applications in dynamic random access memories (DRAM), field effect transistor (FET), and tunable devices because of its properties such as high dielectric constant, low leakage current, low dielectric loss, and high dielectric breakdown strength. Several approaches have been used to optimize the dielectric and electrical properties of BST thin films such as doping, graded compositions, and multilayer structures. We have found that inserting a ZrO2 layer in between two BST layers results in a significant reduction in dielectric constant, loss tangent, and leakage current in the multilayer thin films. Also it is shown that the properties of multilayer structure are found to depend strongly on the sublayer thicknesses. In this work the effect of ZrO2 layer thickness on the dielectric, ferroelectric as well as electrical properties of BST/ZrO2/BST multilayer structure is studied. The multilayer Ba0.8Sr0.2TiO3/ZrO2/Ba0.8Sr0.2TiO3 film is deposited by a sol-gel process on the platinized Si substrate. The thickness of the middle ZrO2 layer is varied while keeping the top and bottom BST layer thickness as fixed. It is observed that the dielectric constant, dielectric loss tangent, and leakage current of the multilayer films reduce with the increase of ZrO2 layer thickness and hence suitable for memory device applications. The ferroelectric properties of the multilayer film also decrease with the ZrO2 layer thickness. INTRODUCTION Over the last decade, (BaxSr1-x)TiO3 (BST) has been investigated intensively for tunable device and memory device applications. Nowadays Ba0.8Sr0.2TiO3 ferroelectric thin film has the highest potential for application in several frequency agile microwave devices such as phase shifters, filters and varactors because of its high dielectric constant, low dielectric loss, and improved dielectric tunability and also for memory devices due to its low leakage current[1,2]. Various efforts have been made to optimize the dielectric and electrical properties of BST thin films for different devices applications. Among the different approaches to optimize the properties in BST thin films, recently, a multilayer structure with a combination of BST and other dielectrics has been proven to be useful approach to improve the properties of BST film. Various multilayer structures with BST as the main constituent have been studied, for improving