Anode for a solid electrolytic capacitor containing a non-metallic surface treatment

Abstract

A solid electrolytic capacitor comprises an anode, a dielectric layer overlying the anode; and a cathode that contains a solid electrolyte layer overlying the dielectric layer. The anode comprises a porous, sintered body that defines a surface. The body is treated so that the surface contains a non-metallic element having a ground state electron configuration that includes five or more valence electrons at an energy level of three or more (e.g., phosphorous).

Description

Anodes of Solid Electrolytic Capacitors Containing Non-Metallic Surface Treatment Background technique Electrolytic capacitors are typically formed from a valve action material that can be oxidized to form a dielectric layer. Typical valve action materials are niobium and tantalum. Capacitors have also been developed to use anodes formed from conductive niobium oxide and niobium pentoxide dielectrics. Despite the benefits of such niobium oxide capacitors, they typically have limited application at high voltages (eg, rated voltages of 16, 20 or 35 volts) because of the relatively low breakdown strength of the dielectric. In general, as the charge and voltage on the capacitor grow, the free electrons will eventually accelerate to a speed at which they can release additional electrons during an avalanche breakdown of collisions with neutral atoms or molecules, which occurs fairly suddenly (usually on the order of nanoseconds), thereby forming a conductive path through the mat...

AI Technical Summary

Problems solved by technology

This leads to unstable leakage current under accelerated temperature and voltage loads, which will limit the application of this type of capacitor in the high voltage field

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