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Title: CMOS RFIC Inductors Incorporated with Domain Patterned Permalloy Films and Investigation of Domain Dynamics therein
Researcher: Vasu Pulijala
Guide(s): Dr. Syed Azeemuddin
Keywords: Domain walls
Magnetic domains
On-chip inductor
University: International Institute of Information Technology, Hyderabad
Completed Date: 08/01/2016
Abstract: Inductors are one of the major constraints in the design of RFICs. This is because they consume large area and the quality factor is very low. Low quality factor is attributed to the parasitic losses at the higher frequencies. Substrate eddy current losses is one among the contributing parasitic losses. To improve the inductance density and quality factor of on-chip spiral inductors in RFICs employment of magnetic materials is one of the popular approaches. In cases where bulk magnetic material is used around inductors, eddy current losses become significant at higher frequencies restricting their usage to lower frequencies. Patterning the magnetic material has shown to reduce these drawbacks. For magnetic materials, formation of magnetic domains and their dynamics may play a major role in defining their properties at higher frequencies. In this thesis, effect of size and shape of Permalloy patterns in the formation of magnetic domains, their dynamics, and the influence of these domain controlled patterns on properties of spiral inductor are investigated. It is shown experimentally that the shape and size induced domain patterns in Permalloy play a varied role in the improvement of inductance. Micromagnetic simulations with OOMMF are used to determine the domain patterns. Secondly, 60 nm thick domain-patterned-Permalloy have given more improvement in inductance and quality factor compared to 96 nm thick patterns. OOMMF simulations show the same trend that 60 nm patterns which contain cross tie walls perform better than 96 nm patterns which contain asymmetric Bloch wall. Permalloy domain-controlled patterns have also been incorporated as magnetic shield and an improvement in the performance of the inductors is observed. All the experimental observations confirm the necessity of incorporation of proper magnetic patterns whose shape and size could be controlled to form appropriate domain patterns for high frequency applications like inductors in RFICs.
Pagination: xv, 89
Appears in Departments:Department of Electronic and Communication Engineering

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01_title.pdfAttached File45.5 kBAdobe PDFView/Open
02_certificates.pdf22.83 kBAdobe PDFView/Open
03_acknowledgement.pdf33.78 kBAdobe PDFView/Open
04_contents.pdf48.14 kBAdobe PDFView/Open
05_preface.pdf35 kBAdobe PDFView/Open
06_list of tables and figures.pdf97.33 kBAdobe PDFView/Open
07_chapter 1.pdf139.05 kBAdobe PDFView/Open
08_chapter 2.pdf1.3 MBAdobe PDFView/Open
09_chapter 3.pdf3.94 MBAdobe PDFView/Open
10_chapter 4.pdf4.87 MBAdobe PDFView/Open
11_chapter 5.pdf737.83 kBAdobe PDFView/Open
12_chapter 6.pdf60.24 kBAdobe PDFView/Open
13_appendices.pdf342.34 kBAdobe PDFView/Open
14_references.pdf74.46 kBAdobe PDFView/Open

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