Modeling and validation of ESR and frequency-stability of high-density nanostructured capacitors for embedded power converters

Spurney, Robert G.; Sharma, Himani; Pulugurtha, Markondeya Raj; Tummala, Rao; Lollis, Naomi; Weaver, Mitch; Gandhi, Saumya; Romig, Matt; Brumm, Holger

doi:10.1016/j.mee.2021.111593

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…Due to the large capacitance density, wide operating temperature range and excellent frequency characteristics, tantalum electrolytic capacitors are an essential passive component in filtering, bypassing, rectification, coupling and energy conversion. [1][2][3][4][5][6][7] With the rapid development of the electronics industry and the demand for comfort of terminal products, electronic devices are gradually developing in the direction of thinness, flexibility and wearability. 8,9 Tantalum electrolytic capacitors are therefore in high demand to become thinner and easier to integrate with silicon wafer, glass and Polyimide (PI).…”

Section: Supplementary Materials For This Article Is Available Onlinementioning

confidence: 99%

Morphological Evolution of Corrosion Pits on the (200) and (211) Surfaces of Tantalum Foil

Zhao¹,

Xu²,

Sun³

et al. 2023

J. Electrochem. Soc.

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As an extremely passive metal, tantalum is often used as an additive element in corrosion-resistant alloys. Although the electrochemical corrosion mechanisms of these tantalum-based alloys have been extensively studied, the corrosion properties of the tantalum metal itself have received little attention. In this study, we developed a numerical simulation model to qualitatively describe the propagation of corrosion pits on different crystal surfaces of tantalum. The morphological characteristics of the corrosion pits predicted by the model are in high agreement with those observed by scanning electron microscopy, indicating the validity of the model. Due to the difference in crystallographic orientation, the corrosion pits on the surface of (200) have a square shape while those on the surface of (211) have an inverted triangle shape. Although the dimensions of the two types of pits are close, the square pit is more likely to develop deeper and thus the (200) surface exhibits a higher specific surface area. Therefore, the present work provides a reference for the fabrication of etched foils for tantalum electrolytic capacitors.

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Section: Supplementary Materials For This Article Is Available Onlinementioning

confidence: 99%

Morphological Evolution of Corrosion Pits on the (200) and (211) Surfaces of Tantalum Foil

Zhao¹,

Xu²,

Sun³

et al. 2023

J. Electrochem. Soc.

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An Ultra‐Thin, Ultra‐High Capacitance Density Tantalum Capacitor for 3D Packaging

Zhao

Hou

et al. 2023

Adv Materials Technologies

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Although embedded capacitors have been applied and researched for many years, their large‐scale application still faces challenges such as low capacitance density, high thickness, high cost, and incompatibility with integrated processes. In this work, a breakthrough has been made in the fabrication of ultra‐thin tantalum (Ta) capacitors with ultra‐high capacitance density that can be used for 3D packaging. The key to these excellent performances is the application of Ta foil with nano‐porous structure to the anode of the capacitor. The Ta foil with high specific surface area (SSA) is successfully prepared by direct current pulse etching. At a current density of 15 mA cm−2, a pulse frequency of 50 Hz, and a duty cycle of 30%, the SSA of Ta foil is increased by 76 times after etching in an electrolyte with 0.01 v% TOA for 30 min. Based on this, Ta capacitors with a form factor of less than 40 µm, showing a capacitance density of 750 nF mm−2 and a leakage current of less than 2.1 × 10−7 A at 8 V is successfully fabricated. To the best of the authors’ knowledge, this is the highest capacitance density reported to date for the mentioned form factors.

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Modeling and validation of ESR and frequency-stability of high-density nanostructured capacitors for embedded power converters

Cited by 2 publications

References 14 publications

Morphological Evolution of Corrosion Pits on the (200) and (211) Surfaces of Tantalum Foil

Morphological Evolution of Corrosion Pits on the (200) and (211) Surfaces of Tantalum Foil

An Ultra‐Thin, Ultra‐High Capacitance Density Tantalum Capacitor for 3D Packaging

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