# US 2016/0186362 A1 · Substrates for semiconductor devices

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- Number: US 2016/0186362 A1
- Document ID: US20160186362A1
- Status: Published application
- Kind: A1
- Application number: 14/648,256
- Filed: 2013-12-04
- Published: 2016-06-30
- Earliest claimed: 2012-12-18
- Assignees: Element Six Limited
- Applicants: Element Six Limited
- Inventors: Timothy Mollart; Quanzhong Jiang; Michael John Edwards; Duncan Allsopp; Christopher Rhys Bowen; Wang Nang Wang
- Web page: https://patentgrep.com/patent/US20160186362A1

## CPC

- C30B 25/18: characterised by the substrate
- C23C 16/27: Diamond only
- C30B 25/183: {being provided with a buffer layer, e.g. a lattice matching layer}
- C30B 29/04: Diamond
- C30B 29/36: Carbides
- C30B 29/40: AIIIBV compounds {wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi}
- C30B 29/403: {AIII-nitrides}
- C30B 29/406: {Gallium nitride}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2903: {Carbon, e.g. diamond-like carbon}
- H10P 14/2924: {Structures}
- H10P 14/2926: {Crystal orientations}
- H10P 14/3211: {Silicon, silicon germanium or germanium}
- H10P 14/3256: {Microstructure}
- H10P 14/3402: {characterised by the chemical composition}
- H10P 14/3414: {being group IIIA-VIA materials}
- H10P 14/3416: {Nitrides}
- H10W 40/254: {Diamond}
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method of fabricating a composite semiconductor component comprising: (i) providing a bowed substrate comprising a wafer of synthetic diamond material having a thickness td, the bowed substrate being bowed by an amount B and comprising a convex face and a concave face; (ii) growing a layer of compound semiconductor material on the convex face of the bowed substrate via a chemical vapour deposition technique at a growth temperature T to form a bowed composite semiconductor component comprising the layer of compound semiconductor material of thickness tsc on the convex face of the bowed substrate, the compound semiconductor material having a higher average thermal expansion coefficient than the synthetic diamond material between the growth temperature T and room temperature providing a thermal expansion mismatch ΔTec; and (iii) cooling the bowed composite semiconductor component, wherein the layer of compound semiconductor material contracts more than the wafer of synthetic diamond material during cooling due to the thermal expansion mismatch ΔTec, wherein B, td, tsc, and ΔTec are selected such that the layer of compound semiconductor material contracts on cooling by an amount which off-sets bowing in the bowed substrate thus pulling the bowed composite semiconductor component into a flat configuration, the layer of compound semiconductor material having a tensile stress after cooling of less than 500 MPa.

## Claims

### Claim at position 1

1-6. (canceled)

### Claim 7

A composite semiconductor component comprising:
a substrate comprising a wafer of synthetic diamond material; and
a layer of compound semiconductor material on the substrate,
wherein the layer of compound semiconductor material has a tensile stress of less than 500 MPa at room temperature.

### Claim 8 (depends on 7)

A composite semiconductor component according to claim 7, wherein the tensile stress of the layer of compound semiconductor material is less than 450 MPa, 400 MPa, 350 MPa, 300 MPa, 250 MPa, or 210 MPa at room temperature.

### Claim 9 (depends on 7)

A composite semiconductor component according to claim 7, wherein the substrate comprises a layer of single crystal material disposed between the wafer of synthetic diamond material and the layer of compound semiconductor material.

### Claim 10 (depends on 7)

A composite semiconductor component according to claim 7, wherein a spacing between the layer of compound semiconductor material and the wafer of synthetic diamond material is no more than 5 μm, 3 μm, 2 μm, or 1 μm.

### Claim 11 (depends on 7)

A composite semiconductor component according to claim 7, wherein the substrate comprises a layer of material disposed on an opposite side of the wafer of synthetic diamond material to the layer of compound semiconductor material, said layer of material having a lower thermal expansion coefficient than the synthetic diamond material at a temperature below 700° C.

### Claim 12 (depends on 7)

A composite semiconductor component according to claim 7, wherein the synthetic diamond material has a thermal conductivity equal to or greater than 600 Wm−1K−1, 800 Wm−1K−1, 1000 Wm−1K−1, 1200 Wm−1K−1, or 1400 Wm−1K−1.

### Claim 13 (depends on 7)

A composite semiconductor component according to claim 7, wherein the synthetic diamond material has a thickness in a range: 25 μm to 450 μm; 25 μm to 400 μm; 25 μm to 350 μm; 25 μm to 300 μm; 25 μm to 250 μm; 25 μm to 200 μm; 25 μm to 150 μm; 40 μm to 130 μm; or 50 μm to 100 μm.

### Claim 14 (depends on 7)

A composite semiconductor component according to claim 7, wherein the synthetic diamond material is formed of a single crystal diamond material or a polycrystalline CVD diamond material.

### Claim 15 (depends on 7)

A composite semiconductor component according to claim 7, wherein the wafer of synthetic diamond material comprises a free-standing synthetic diamond wafer or a wafer which comprises a layer of synthetic diamond material on a support substrate.

### Claim 16 (depends on 7)

A method of fabricating a composite semiconductor component according to claim 7, the method comprising:
(i) providing a bowed substrate comprising a wafer of synthetic diamond material having a thickness td, the bowed substrate being bowed by an amount B and comprising a convex face and a concave face;
(ii) growing a layer of compound semiconductor material on the convex face of the bowed substrate via a chemical vapour deposition technique at a growth temperature T to form a bowed composite semiconductor component comprising the layer of compound semiconductor material of thickness tsc on the convex face of the bowed substrate, the compound semiconductor material having a higher average thermal expansion coefficient than the synthetic diamond material between the growth temperature T and room temperature providing a thermal expansion mismatch ΔTec and
(iii) cooling the bowed composite semiconductor component, wherein the layer of compound semiconductor material contracts more than the wafer of synthetic diamond material during cooling due to the thermal expansion mismatch ΔTec,
wherein B, td, tsc, and ΔTec are selected such that the layer of compound semiconductor material contracts on cooling by an amount which off-sets bowing in the bowed substrate thus pulling the bowed composite semiconductor component into a flat configuration, the layer of compound semiconductor material having a tensile stress after cooling of less than 500 MPa.

### Claim 17 (depends on 16)

A method according to claim 16, wherein B, td, tsc, and ΔTec are selected such that the tensile stress of the layer of compound semiconductor material after cooling is less than 450 MPa, 400 MPa, 350 MPa, 300 MPa, 250 MPa, or 210 MPa.

### Claim 18 (depends on 16)

A method according to claim 16, wherein the bowed substrate comprises a layer of single crystal material on the convex face of the bowed substrate, the layer of compound semiconductor material being grown on said layer of single crystal material.

### Claim 19 (depends on 16)

A method according to claim 16, wherein the bowed substrate comprises a layer of material on the concave face of the bowed substrate which has a lower average thermal expansion coefficient than the synthetic diamond material between the growth temperature T and room temperature, said layer of material having a thermal expansion coefficient and thickness which are selected to contribute in off-setting the bowing in the bowed substrate during cooling.

### Claim 20 (depends on 16)

A method according to claim 16, wherein the wafer of synthetic diamond material has a thermal conductivity equal to or greater than 600 Wm−1K−1, 800 Wm−1K−1, 1000 Wm−1K−1, 1200 Wm−1K−1, or 1400 Wm−1K−1.

### Claim 21 (depends on 16)

A method according to claim 16, wherein the thickness td of the wafer of synthetic diamond material is in a range: 25 μm to 450 μm; 25 μm to 400 μm; 25 μm to 350 μm; 25 μm to 300 μm; 25 μm to 250 μm; 25 μm to 200 μm; 25 μm to 150 μm; 40 pm to 130 μm; or 50 μm to 100 μm.