Date of Award

8-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering (Holcomb Dept. of)

Committee Member

Dr. William R. Harrell, Committee Chair

Committee Member

Dr. Yuri P. Freeman

Committee Member

Dr. Goutam Koley

Abstract

Polymer Hermetic Sealed (PHS) Tantalum capacitors are advanced Polymer Tantalum capacitors with moisture sealed in the capacitor via hermetically sealing the device inside a package. Their attractive features include high volumetric efficiency, leakage current stability, and low weight as compared to wet and solid-state polymer Ta capacitors. Moreover, recent studies have observed certain interesting properties in PHS Ta capacitors like Breakdown Voltage (BDV) being greater than Formation Voltage, anomalous transient currents, and Capacitance Stability issues. In this thesis, a technique to accurately perform the electrical characterization of thin-film MIS polymer Ta capacitors is established in order to understand the properties observed in PHS Ta capacitors. BDV greater than Formation Voltage is observed in these thin-film MIS capacitors which bolsters our hypothesis that this amazing phenomenon is primarily due to the material layers and their interactions, as opposed to being primarily due to the complex structure of KEMET’s PHS Ta capacitors. Moreover, Capacitance Stability is observed in thin-film MIS devices. The C(T) results are observed to be closely following the dielectric constant k(T) for almost the entire range of temperature, i.e., -55˚C to 150˚C. This result suggests that the thin-film MIS capacitors have capacitance dependence on temperature primarily due to the natural dependence of its dielectric material. In addition, Poole-Frenkel leakage mechanism is observed in some of the thin-film MIS capacitors. Thin-film MIS capacitors are established as viable, inexpensive, and easily fabricated models of KEMET PHS Ta capacitors to improve the Capacitance Stability and Breakdown Voltages of existing PHS Ta capacitors.

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