Shapeable short circuit resistant capacitor
View Patent ↗A ceramic short circuit resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The capacitor that exhibits a benign failure mode in which a multitude of discrete failure events result in a gradual loss of capacitance. Each event is a localized event in which localized heating causes an adjacent portion of one or both of the electrodes to vaporize, physically cleaning away electrode material from the failure site. A first metal electrode, a second metal electrode, and a ceramic dielectric layer between the electrodes are thin enough to be formed in a serpentine-arrangement with gaps between the first electrode and the second electrode that allow venting of vaporized electrode material in the event of a benign failure.
1. A shapeable, short-resistant capacitor, comprising:
a first metal electrode having a thickness that is less than about 0.3 microns;
a second metal electrode having a thickness that is less than about 0.3 microns; and
a ceramic dielectric layer disposed between the first metal electrode and the second metal electrode, wherein a stack comprising the first metal electrode, the second metal electrode, and the ceramic dielectric layer is formed in a serpentine arrangement with gaps defined between opposing parallel portions of the first metal electrode and between opposing parallel portions of the second metal electrode, wherein said gaps allow venting of evaporated electrode material in the event of a benign failure.
2. The capacitor of claim 1 , wherein the first metal electrode is formed of a material selected from the group consisting of nickel, aluminum, copper, zinc, silver, gold, platinum, titanium, chrome and tungsten.
3. The capacitor of claim 2 , wherein the first metal electrode has a thickness of about 0.1 micrometers to 1 micrometers.
4. The capacitor of claim 1 , wherein the second metal electrode is formed of a material selected from aluminium, platinum, copper, zinc, silver, gold and combinations of these metals.
5. The capacitor of claim 4 , wherein the second metal electrode has a thickness of about 0.01 micrometers to about 0.1 micrometers.
6. The capacitor of claim 1 , wherein the ceramic dielectric layer is formed of lead lanthanum zirconium titanate (PLZT).
7. The capacitor of claim 6 , wherein the ceramic dielectric layer has a thickness of about 0.1 micrometers to about 4 micrometers.