Dielectric Response of Tantalum Oxide Deposited on Polyethylene Terephthalate (PET) Film by Low-Temperature Pulsed-DC Sputtering for Wound Capacitors

Abstract

Deposition of high-k tantalum oxide thin films on thin polymer substrates was investigated, using lowtemperature (−100°C) pulsed-dc reactive sputtering. Degradation of two different polymers, polyethylene terephthalate (PET) and polypropylene (PP), were studied as a function of sputtering conditions. Two different deposition configurations have been explored for polymer films with aluminum electrode on one side. In one configuration, tantalum oxide was deposited on the nonelectroded side of the polymer, while in the other the deposition was on the electroded side of the polymer. The two fabricated structures have been characterized for dielectric permittivity, loss, and ac conductivity as a function of frequency and temperature. Sputtering tantalum oxide on the nonelectroded side of PET substrates results in a 37% higher permittivity for PET than the series model prediction of permittivity. Higher dielectric loss and ac conductivity accompany the higher permittivity. The α bulk relaxation in PET moves to slightly higher temperatures, indicating that there is an increase in the crystallinity of the bulk polymer. This observation is supported by the broader glass transition and an additional endothermic peak around 200°C in PET/Ta 2 O 5 compared to neat PET. In addition, modifications of the space charge activation energy in PET from 1.35 eV to 1.82 eV and of dc conductivity in PET from 6×10 −15 S/m to 4×10 −14 S/m is observed. Sputtering Ta 2 O 5 on the electroded side of the PET, under the same sputtering conditions, results in the formation of high-k tantalum oxide with dielectric permittivity,

Performance and Reliability of Electrowetting-on-Dielectric (EWOD) Systems Based on Tantalum Oxide

“…The error bars are wide, indicating the highly variable nature of breakdown in these films. This finding is consistent with what has been observed in similar TaOx films undergoing MOM measurements, with typical values ranging from 2.2 to 4 MV cm –1 . − …”

Roll your own – nano-nanocomposite capacitors

“…To this end, the U.S. Navy and Air Force have supported signicant programs to develop superior wound capacitors. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Although the literature to date does describe processing of ceramic/polymer nanocomposite lms for capacitor applications, there are yet no reports that demonstrate such lms can be sufficiently exible to be rolled especially with high vol% of nanoceramic particles. The potential to realize wound capacitors with much higher energy densities is likely to greatly change energy storage device manufacture, at least in some high-end applications.…”

A Simple Model for Mechanical Behavior of PET Thin Film Deposited with Pure Aluminum on Both Surfaces and the Experimental Study

“…Traditional applications of PET materials can be found in a wide range from the packaging industry, the apparel industry where polyester fiber is an excellent choice, the mechanical engineering where textiles made of PET fiber are generally adopted in conveyor belts and tire cords to bear the external mechanical loadings, to the civil engineering where the thin films or sheets made from polyester are chosen to utilize their high tensile strength and good chemical stability. And now the application of PET has been extended to electric and electronic engineering and this material is used to manufacture cables, capacitors or acts as the substrate of MEMS components [2]. In addition, mechanical recycling of PET can re-use products of the material conveniently with less toxicity [3].…”