Ceramic components, coated structures and methods for making same
Methods of forming ceramic components are disclosed. One method calls for chemical vapor depositing a ceramic material over a substrate having first and second opposite surfaces to define a coated structure, the ceramic material forming a layer overlying both the first and second opposite surfaces. The layer and the substrate have a difference in thermal expansion coefficients of at least 0.5 ppm/K. The substrate is removed, leaving behind the layer. Ceramic components and coated structures are also disclosed.
1 . A method of forming a ceramic component, comprising:
providing a substrate first and second opposite major surfaces, wherein the first and second major surfaces are substantially parallel to each other and are separated by a thickness of the substrate;
forming a first pattern within the substrate, wherein the first pattern extends form the first opposite major surface;
chemical vapor depositing a ceramic material over a substrate to define a coated structure, the ceramic material forming a layer along each of the first and second opposite major surfaces and within the first pattern, the layer and the substrate having a difference in thermal expansion coefficients of at least 0.5 ppm/K; and
removing the substrate leaving behind the layer.
2 . The method of claim 1 , wherein the substrate is a wafer.
3 . The method of claim 1 , wherein the first pattern extends partly but not completely to the second opposite major surface of the substrate.
4 . The method of claim 3 , further comprising forming a second pattern extending along the second opposite major surface.
5 . The method of claim 3 , wherein the pattern comprises microfeatures.
6 . The method of claim 5 , wherein the microfeatures have a critical dimension not greater than about 500 microns.
7 . The method of claim 6 , wherein the critical dimension is not greater than about 200 microns.
8 - 13 . (canceled)
14 . The method of claim 1 , wherein the difference in thermal expansion coefficients is not less than 0.75 ppm/K.
15 - 42 . (canceled)
43 . A method of forming a ceramic component, comprising:
depositing a polycrystalline ceramic material over a substrate to form a layer overlying the substrate, wherein depositing comprises (i) chemical vapor depositing a first film comprised of the polycrystalline ceramic material; (ii) cooling the substrate and the first film; and (iii) chemical vapor depositing a second film comprised of the polycrystalline ceramic material to overlie the first film, wherein the layer comprises the first and second films, and the layer and the substrate have a difference in thermal expansion coefficients of at least 0.5 ppm/K; and
removing the substrate leaving behind the layer.
44 - 46 . (canceled)
47 . The method of claim 45 , wherein the pattern comprises microfeatures.
48 . The method of claim 47 , wherein the microfeatures have a critical dimension not greater than about 200 microns.
49 - 50 . (canceled)
51 . The method of claim 47 , further comprising processing the deposited ceramic material to form a plurality of ceramic components.
52 . The method of claim 51 , wherein the microfeatures comprise a pattern of microfeature groups, each microfeature group defining a complementary microfeature group in the layer, each complementary microfeature group defining an individual ceramic component of the plurality of ceramic components.
53 . The method of claim 51 , wherein the plurality of ceramic components comprise a plurality of MEMS or MMS ceramic components.
54 - 57 . (canceled)
58 . The method of claim 43 , wherein the polycrystalline ceramic material comprises SiC.
59 . (canceled)
60 . The method of claim 43 , wherein the substrate comprises silicon.
61 . The method of claim 60 , wherein the substrate consists essentially of silicon.
62 . (canceled)
63 . The method of claim 43 , wherein the layer has a thickness not less than 50 microns.
64 - 68 . (canceled)
69 . The method of claim 43 , wherein the first film is deposited at a first deposition rate r 1 and the second film is deposited at a second deposition rate r 2 , wherein r 2 >2r 1 .
70 . (canceled)
71 . The method of claim 43 , wherein the first and second films are deposited at a temperature not less than 800° C. and not greater than 1300° C.
72 . The method of claim 43 , wherein cooling is carried out at a temperature not greater than 400° C.
73 - 74 . (canceled)
75 . The method of claim 43 , wherein the film is deposited to a thickness t 1 and the second film is deposited to a thickness t 2 , wherein t 2 >2t 1 .
76 - 115 . (canceled)
116 . A method of depositing a silicon carbide layer, comprising:
depositing a first polycrystalline silicon carbide film over a patterned silicon substrate by chemical vapor deposition at a temperature not less than 800° C. and at a rate r 1 , the first polycrystalline silicon carbide film having a thickness t 1 ;
cooling the substrate and the first film to a temperature not greater than 400° C. after depositing the first silicon carbide film; and
depositing a second polycrystalline silicon carbide film over the first polycrystalline silicon carbide film by chemical vapor deposition at a temperature not less than 800° C. and at a rate r 2 , the second polycrystalline silicon carbide film having a thickness t 2 ;
wherein t 2 >2t 1 , r 2 >2r 1 , and the silicon carbide layer is comprised of the first and second polycrystalline silicon carbide films, the silicon carbide layer having a thickness not less than 30 microns.
117 - 119 . (canceled)
120 . The method of claim 116 , wherein each of depositing a first polycrystalline silicon carbide film and depositing a first polycrystalline silicon carbide film is performed at a temperature not greater than 1300° C.