Reactive flow deposition and synthesis of inorganic foils

• US 20090017292A1
• Filed: 06/12/2008
• Published: 01/15/2009
• Est. Priority Date: 06/15/2007
• Status: Abandoned Application

• Current Assignee: Nanogram Corporation (Teijin Limited)
• Original Assignee: Nanogram Corporation (Teijin Limited)
• Inventors: Solayappan, Narayan, Morris, Julio E., Chiruvolu, Shivkumar, Hieslmair, Henry, Mosso, Ronald J.
• Application Number:
  US12/157,713
• Publication Number:
  US 20090017292A1
• Time in Patent Office: Days
• US Class Current: 428/336
• CPC Class Codes: C23C 16/01 on temporary substrates, e.g. substrates subsequently removed by etching
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• CPC Class Codes: C23C 16/545 for coating elongated substrates
• CPC Class Codes: C30B 13/00 Single-crystal growth by zone-melting; Refining by zone-melting C30B17/00 takes precedence; by changing the cross-section of the treated solid C30B15/00; under a protective fluid C30B27/00; for the growth of homogeneous polycrystalline material with defined structure C30B28/00
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02513 Microstructure
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/1872 Recrystallisation
• CPC Class Codes: H01L 31/202 including only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/263 Coating layer not in excess of 5 mils thick or equivalent
• CPC Class Codes: Y10T 428/264 Up to 3 mils
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

Sub-atmospheric pressure chemical vapor deposition is described with a directed reactant flow and a substrate that moves relative to the flow. Thus, using this CVD configuration a relatively high deposition rate can be achieved while obtaining desired levels of coating uniformity. Deposition approaches are described to place one or more inorganic layers onto a release layer, such as a porous, particulate release layer. In some embodiments, the release layer is formed from a dispersion of submicron particles that are coated onto a substrate. The processes described can be effective for the formation of silicon films that can be separated with the use of a release layer into a silicon foil. The silicon foils can be used for the formation of a range of semiconductor based devices, such as display circuits or solar cells.

Claims

1. A method for forming an inorganic layer on a release layer supported on a substrate, the method comprising:

depositing an inorganic layer onto a porous, particulate release layer using chemical vapor deposition.

2. The method of claim 1 wherein the depositing step is performed in a reaction chamber at a pressure from about 50 Torr to about 650 Torr and at a pressure below ambient pressure.

3. The method of claim 1 wherein the reactants for the chemical vapor deposition process flow from an inlet of a nozzle oriented to direct flow from the inlet to the release layer.

4. The method of claim 1 wherein the chemical vapor deposition reaction comprises a thermal decomposition reaction.

5. The method of claim 4 wherein the inorganic layer comprises elemental silicon.

6. The method of claim 1 wherein the release layer comprises a fused network of submicron particles.

7. The method of claim 1 wherein the release layer is formed through the deposition of a dispersion of particles.

8. The method of claim 1 wherein the substrate is heated to facilitate the chemical vapor deposition.

9. The method of claim 1 wherein the chemical vapor deposition is enhanced using a plasma, a heated filament or an electron beam.

10. The method of claim 1 wherein a porous, particulate under-layer is positioned under the porous, particulate layer, wherein the porous, particulate under-layer has a larger primary particle size relative to the porous, particulate layer.

11. A method for depositing an inorganic layer, the method comprising:

depositing an inorganic material using chemical vapor deposition onto a substrate that is moving relative to a flow of reactants delivered from a nozzle inlet in a reaction chamber with a pressure from about 50 Torr to about 700 Torr and at a pressure below ambient pressure.

12. The method of claim 11 wherein the nozzle is fixed with respect to the reaction chamber and the substrate moves relative to the reaction chamber.

13. The method of claim 11 wherein the substrate is heated to facilitate a thermal reaction to form a product composition at the substrate.

14. The method of claim 11 wherein the inorganic material comprises elemental silicon and wherein the reactants undergo a thermal decomposition reaction.

15. The method of claim 11 wherein an exhaust conduit from the reaction chamber is positioned adjacent the nozzle inlet.

16. The method of claim 11 wherein the pressure is from about 75 Torr to about 600 Torr.

17. A layered structure comprising a substrate, a powder layer on the substrate and an approximately dense silicon layer deposited onto the powder layer wherein the silicon layer has a thickness from about 2 microns to about 100 microns.

18. The layered structure of claim 17 wherein the layer has a thickness from about 10 microns to about 60 microns.

19. The layered structure of claim 17 wherein the powder layer comprises silicon nitride, silicon oxide, silicon oxynitride or combinations thereof.

20. The layered structure of claim 17 wherein the powder layer has a thickness form about 50 nm to about 50 microns.

21. The layered structure of claim 17 wherein the layer has a surface area or at least about 100 square centimeters.

22. A method for forming an inorganic layer on a release layer, the method comprising:

forming a power coating on a substrate wherein the formation of the coating comprises depositing a particle dispersion onto a substrate; and

depositing an inorganic composition onto the powder coating from a reactive flow in which the reactive flow is initiated from an inlet of nozzle directed at the substrate.

23. The method of claim 22 wherein the dispersion comprises particles having a volume average secondary particle size of no more than about 2 microns and a particle concentration of at least about 2 weight percent.

24. The method of claim 22 wherein the depositing of the particle dispersion comprises spin coating the dispersion.

25. The method of claim 22 wherein the particle dispersion comprises particles that are surface modified with a chemically bonded organic composition.

26. The method of claim 22 where the reactant flow passes through a light beam to drive a reaction to form a product flow that is directed to the substrate.

27. The method of claim 22 wherein the depositing of the inorganic compositions comprises chemical vapor deposition.