Substrate including a diamond layer and a composite layer of diamond and silicon carbide, and, optionally, silicon

1. A multilayer substrate comprising:

a composite layer comprised of diamond particles and silicon carbide particles; and

a chemical vapor deposition (CVD) grown diamond layer on the composite layer, wherein diamond of the diamond layer is CVD grown on crystal surfaces of the diamond particles and/or the silicon carbide particles comprising the composite layer, wherein the diamond layer comprises polycrystalline diamond, wherein the composite layer is comprised of silicon articles.

2. The multilayer substrate of claim 1 , wherein the diamond layer is one of the following:

un-doped;

doped with an n-type element or compound;

doped with a p-type element or compound; or

doped with boron.

3. The multilayer substrate of claim 1 , wherein the diamond layer is patterned or selectively etched.

4. The multilayer substrate of claim 1 , wherein the diamond particles in the composite layer have a concentration gradient in the composite layer between 0% and 100%.

5. The multilayer substrate of claim 1 , wherein a loading level (by volume) of diamond particles in the composite layer is one of the following:

≧5%;

≧20%;

≧40%; or

≧60%.

6. The multilayer substrate of claim 1 , wherein a thickness of the diamond layer is one of the following:

between 10 −9 meters and 10− 6 meters;

between 5×10 −6 meters and 20×10 −3 meters;

between 500×10 −6 meters and 10×10 −3 meters;

between 1×10 −6 meters and 5×10 −3 meters;

between 3×10 −6 meters and 3×10 −3 meters;

between 50×10 −6 meters and 50×10 −2 meters;

between 100×10 −6 meters and 10×10 −2 meters;

between 200×10 −6 meters and 5×10 −2 meters; or between 500×10 −6 meters and 2×10 −2 meters.

7. The multilayer substrate of claim 1 , wherein a thickness of the multilayer substrate is one of the following:

≧200×10 −6 meters;

≧20×10 −3 meters;

≧40×10 −3 meters;

≧75×10 −3 meters;

≧50×10 −6 meters;

≧500×10 −6 meters; or

≧1×10 −3 meters.

8. The multilayer substrate of claim 1 , wherein the multilayer substrate has one of the following shapes or a combination of two or more of the following shapes:

circle,

square,

rectangle,

polygon,

ellipse,

curve,

sphere,

aspheric,

cylinder,

cone,

concave, or

convex.

9. The multilayer substrate of claim 1 , wherein a surface of the diamond layer is grown or polished to desired roughness and flatness values.

10. The multilayer substrate of claim 1 , configured for use as one of the following:

an optical device;

a detector for detecting high energy radiation particles;

a detector for detecting electromagnetic waves;

a device for cutting, drilling, machining, milling, lapping, polishing, coating, bonding, or brazing;

a braking device;

a seal;

a heat conductor;

an electromagnetic wave conducting device;

a chemically inert device configured for use in a highly corrosive environment, a strong oxidizing environment, or a strong reducing environment, at an elevated temperature, or under a cryogenic condition; or

a device for polishing or planarization of semiconductor device, wafer or film, an optical device, wafer or film, and or an electronic device, wafer or film.

11. The multilayer substrate of claim 10 , wherein the optical device is either a planar optic or a non-planar optic.

12. The multilayer substrate of claim 11 , wherein the planar optic is a mirror or a lens.

13. The multilayer substrate of claim 11 , wherein the non-planar optic is spherical, or aspheric, or a cone, or a cylinder.

14. The multilayer substrate of claim 10 , wherein the optical device includes an optical coating for management of electromagnetic waves.

15. A method of forming the multilayer substrate of claim 1 comprising:

(a) forming a composite layer comprised of diamond particles and silicon carbide particles and silicon particles;

(b) positioning the composite layer on a substrate holder of a reactor; and

(c) growing a diamond layer on the composite layer positioned on the substrate holder in the reactor, wherein diamond of the diamond layer grows directly on crystal surfaces of the diamond particles comprising the composite layer, wherein the diamond layer comprises polycrystalline diamond.

16. The method of claim 15 , wherein step (c) includes growing the diamond layer on the composite layer via chemical vapor deposition.

17. The method of claim 15 , wherein step (a) further includes machining, lapping polishing, cutting, or drilling the composite layer.