Self-limiting capacitor formed using a plurality of thin film semiconductor ceramic layers

A method of forming a self-limiting ceramic capacitor comprising:

• (a) forming a mixture of ceramic material having grain boundary equivalent circuitry and exhibiting non-linear resistance characteristics;
• (b) producing a green ceramic tape from said ceramic mixture having a thickness of from about 10 to 250 microns;
• (c) applying a conductive coating on a surface of said green ceramic tape;
• (d) forming a stack from said coated ceramic tape, the stack having non-contiguous first and second sides, the tape arranged in said stack so as to provide interleafing conductive coatings extending from said first and second sides;
• (e) sintering said stack of coated green ceramic tape to laminate them together;
• and
• (f) coating said first and second sides of said laminated stack with conductive material to interconnect said conductive coatings with one or the other of said conductive material on said two sides.

A method of forming a self-limiting ceramic capacitor comprising:

• (a) forming a mixture of ceramic material exhibiting non-linear resistance characteristics and having a particle size range of from about 0.1 to 1.0 microns;
• (b) producing a thin film green ceramic tape from said ceramic mixture having a thickness of from about 25 to 160 microns;
• (c) cutting rectangular segments from said green ceramic tape;
• (d) applying a conductive coating on a surface of a plurality of said rectangular segments of green ceramic tape;
• (e) forming a stack of said rectangular green ceramic tape segments;
• (f) sintering said stack of coated green ceramic tape segments to laminate them together;
• and
• (g) coating two edges of said laminated stack with conductive material to interconnect said conductive coatings on said segments respectively with one or the other of said conductive material on said two edges.

A self-limiting ceramic capacitor device having high capacitance and in situ transient voltage protection properties wherein said capacitor, when exposed to a voltage in excess of the safe operating voltage of said capacitor will act as a varistor and thus limit the voltage until said excess voltage is removed when said device will again act as a capacitor, said capacitor comprising a plurality of thin film layers of semiconducting ceramic characterized by grain boundary equivalent circuitry and non-linear resistance characteristics which permit it to function as a varistor upon exposure to a voltage in excess of the safe operating voltage of the capacitor;

• said thin film layers sintered together to form a laminated stack;
• said thin layers having a conductive coating on at least one surface thereof, some of said conductive coatings extending to a first edge of said stack and at least some of the remainder of said thin layers having said conductive coating extending to a second non-contiguous edge;
• conductive material on said first edge of said laminated stack of thin film ceramic layers and in electrical communication with said conductive coating extending to said first edge to provide a first connected electrode;
• and conductive material on said second edge of said laminated stack and in electrical communication with said conductive coating extending to said second edge to provide a second connected electrode, said electrodes and thin layers of ceramic in combination providing said self-limiting capacitor.

A method of forming a self-limiting ceramic capacitor device having high capacitance and in situ transient voltage protection properties comprising:

• (a) forming a mixture of ceramic material having grain boundary equivalent circuitry and exhibiting non-linear resistance characteristics whereby a capacitor, formed from said ceramic material and exposed to a voltage in excess of the safe operating voltage of said capacitor, will act as a varistor and thus limit the voltage until said excess voltage is removed whereupon said device will again act as a capacitor;
• (b) producing a green ceramic tape from said ceramic mixture having a thickness of from about 10 to 250 microns;
• (c) applying a conductive coating on a surface of said green ceramic tape;
• (d) forming a stack of tape segments from said coated green ceramic tape, said stack having non-contiguous first and second sides, said tape segments arranged in said stack so as to provide interleaving conductive coatings extending from said first and second sides;
• (e) sintering said stack of coated green ceramic tape segments to laminate them together;
• and
• (f) coating said first and second sides of said laminated stack with conductive material to interconnect said conductive coatings on said segments with one or the other of said conductive material on said two sides;
• whereby a self-limiting capacitor device is formed characterized by high capacitance and in situ transient voltage protection.