Passive electrical components formed on carbon coated insulating substrates

• US 20030026991A1
• Filed: 08/13/2002
• Published: 02/06/2003
• Est. Priority Date: 08/10/1999
• Status: Abandoned Application

• Current Assignee: EMC Technology Incorporated (Smiths Group International Holdings Ltd.)
• Original Assignee: EMC Technology Incorporated (Smiths Group International Holdings Ltd.)
• Inventors: Shah, Rajendra, Mazzochette, Joseph B., Helfand, Martin A.
• Application Number:
  US10/219,215
• Publication Number:
  US 20030026991A1
• Time in Patent Office: Days
• US Class Current: 428/408
• CPC Class Codes: H01C 1/084 using self-cooling, e.g. fins, heat sinks
• CPC Class Codes: H01C 17/0652 containing carbon or carbides
• CPC Class Codes: H01C 7/048 Carbon or carbides
• CPC Class Codes: H01L 23/3732 Diamonds
• CPC Class Codes: H01L 27/013 Thick-film circuits
• CPC Class Codes: H01L 27/016 Thin-film circuits
• 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: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A substrate having a diamond or diamond-like carbon coating of at least one micron thickness on an underlayer of an insulating material such as AlN. Such a substrate is advantageously used as a mounting for passive electrical components such as microwave and radio-frequency (rf) resistors, capacitors, attenuators, terminators and loads.

Claims

1. A substrate for electrical components comprising:

an insulating layer having at least a first surface; and

a carbon layer on the first surface.

2. The substrate of claim 1 wherein the carbon layer is diamond.

3. The substrate of claim 1 wherein the carbon layer is diamond-like.

4. The substrate of claim 1 wherein the carbon layer has a thermal conductivity in the range from 2.5 to 12 W/cm°

C. and an electrical resistivity in the range from 10¹⁰ to 10¹⁶ ohm·

cm.

5. The substrate of claim 1 wherein the carbon layer is between about 1 to 1000 microns thick.

6. The substrate of claim 1 wherein the carbon layer is formed by chemical vapor deposition on the ensulating layer.

7. The substrate of claim 1 wherein the carbon layer is formed by hot filament chemical vapor deposition in which methane gas is decomposed.

8. The substrate of claim 1 wherein the insulating layer is made of BeO, Al₂O₃, MgO, BN, AlN or SiC.

9. A circuit comprising:

an insulating layer having at least a first surface;

a carbon layer on the first surface; and

at least one component formed on the carbon layer.

10. The circuit of claim 9 wherein the carbon layer is diamond.

11. The circuit of claim 9 wherein the carbon layer is diamond-like.

12. The circuit of claim 9 wherein the carbon layer has a thermal conductivity in the range from 2.5 to 12 W/cm°

C. and an electrical resistivity in the range from 10¹⁰ to 10¹⁶ ohm·

cm.

13. The circuit as set forth in claim 9 wherein the carbon layer is between about 1 to 1000 microns thick.

14. The circuit of claim 9 wherein the carbon layer is formed by chemical vapor deposition on the insulating layer.

15. The circuit of claim 9 wherein the carbon layer is formed by hot filament chemical vapor deposition in which methane gas is decomposed.

16. The circuit of claim 9 wherein the insulating layer is made of BeO, Al₂O₃, MgO, BN, AlN or SiC.

17. The circuit as set forth in claim 9 wherein the component is a thin film component.

18. The circuit as set forth in claim 9 wherein the component is a thick film component.

19. A method of forming a passive electrical component comprising the steps of:

providing an electrically insulating underlayer;

forming on the underlayer a carbon layer; and

forming at least one of a resistor, a capacitor, an attenuator, a termination or a load on the carbon layer.

20. The method of claim 19 wherein the carbon layer has thermal conductivity in the range from 2.5 to 12 W/cm°

C. and an electrical resistivity in the range from 10¹⁰ to 10¹⁶ ohm·

cm.