Device applications for voltage switchable dielectric material having high aspect ratio particles

• US 7,695,644 B2
• Filed: 07/29/2007
• Issued: 04/13/2010
• Est. Priority Date: 08/27/1999
• Status: Expired due to Fees

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Shocking Technologies, Inc.
• Inventors: Kosowsky, Lex, Fleming, Robert
• Primary Examiner(s): Kopec; Mark
• Assistant Examiner(s): Thomas; Jaison P
• Application Number:
  US11/881,896
• Publication Number:
  US 20080023675A1
• Time in Patent Office: 989 Days
• Field of Search: 252/500, 338/20
• US Class Current: 252/500
• CPC Class Codes: H01C 17/0652 containing carbon or carbides
• CPC Class Codes: H01C 7/1006 Thick film varistors
• CPC Class Codes: H01C 7/105 Varistor cores H01C7/12 takes precedence
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 1/0257 Overvoltage protection
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 1/0373 containing additives, e.g. fillers H05K1/036 takes precedence
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/0257 Nanoparticles inks comprising nanoparticles H05K1/097
• CPC Class Codes: H05K 2201/0738 Use of voltage responsive materials, e.g. voltage switchable dielectric or varistor materials
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2203/0723 Electroplating, e.g. finish plating
• CPC Class Codes: H05K 2203/105 Using an electrical field; Special methods of applying an electric potential electroplating H05K2203/0723
• CPC Class Codes: H05K 3/188 by direct electroplating
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/88 Terminals, e.g. bond pads

Abstract

One or more embodiments provide for a device that utilizes voltage switchable dielectric material having semi-conductive or conductive materials that have a relatively high aspect ratio for purpose of enhancing mechanical and electrical characteristics of the VSD material on the device.

Claims

1. A device comprising:

two or more electrodes separated by a gap; and

a composition of voltage switchable dielectric (VSD) material provided in the gap, the composition of VSD material comprising;

a binder having a concentration by percentage of volume that ranges between 5-99%;

high aspect ratio (HAR) particles, including HAR particles that are (i) inorganic, (ii) conductive or semi-conductive, and (iii) dispersed as nanoscale particles within the binder, wherein the HAR particles have a concentration by percentage of volume that ranges between 0.01-95%; and

a concentration of particles other than HAR particles, the concentration of particles including (i) conductor particles that have a concentration by percentage of volume that ranges between 0-70%, and/or (ii) semiconductor particles that have a concentration by percentage of volume that ranges between 0.0-95%;

wherein the HAR particles and said conductor and/or semiconductor particles are uniformly dispersed within the binder, so as to not be agglomerated or lumped together in the binder;

wherein the HAR particles and said conductor and/or semiconductor particles are combined to provide said composition with a characteristic of being (i) dielectric in absence of a voltage across the gap that exceeds a characteristic voltage level, and (ii) conductive with application of said voltage across the gap exceeding said characteristic voltage level;

and wherein said characteristic voltage level exceeds about 14 volts per mil across the gap.

2. The device of claim 1, wherein the device corresponds to a printed circuit board.

3. The device of claim 2, wherein the VSD material is provided as a layer within the substrate device.

4. The device of claim 2, wherein the VSD material is provided as trace elements on a surface of the substrate device.

5. The device of claim 1, wherein the device is selected from a group consisting of a discrete device, a semi-conductor package, a display device or backplane, a light-emitting diode, and a radio-frequency identification device.

6. The device of claim 1, wherein the conductor and/or semiconductor particles, other than the HAR particles, include a metal or a metal complex.

7. The device of claim 1, wherein the HAR particles are metallic.

8. The device of claim 1, wherein the HAR particles are conductive nanorods.

9. The device of claim 1, wherein the HAR particles are conductive nanowires.

10. The device of claim 1, wherein the HAR particles include antimony tin oxide (ATO).

11. The device of claim 1, wherein the VSD composition includes semiconductive particles and conductor particles other than HAR particles, wherein said semiconductive particles correspond to one or more of silicon, silicon carbide, titanium dioxide, boron nitride, aluminum nitride, nickel oxide, zinc oxide, zinc sulfide, bismuth oxide, cerium oxide, iron oxide, metal or/and complexes.

12. The device of claim 1, wherein the VSD composition includes semiconductive particles and conductor particles other than HAR particles, wherein said semiconductive particles include particles corresponding to a class of oxides, metal nitrides, metal carbides, metal borides, metal sulfides, or a combination thereof.

13. The device of claim 1, wherein the VSD composition includes semiconductive particles other than the HAR particles that include Titanium dioxide (TiO₂).

14. The device of claim 1, wherein the composition of VSD material is formed without sintering.