Solid state conversion of polycrystalline material

Abstract

Systems, devices, and techniques for manufacturing a crystalline material (e.g., large crystal material) through the solid state conversion of a polycrystalline material are described. A device may be configured to concurrently heat a volume of ribbon, such as an alumina ribbon, using multiple heat sources. For example, a first heat source may heat a first volume of the ribbon and a second heat source may concurrently heat a second volume, for example, within the first volume, where the ribbon may comprise polycrystalline material. The concurrent heating may drive grain growth in the polycrystalline material in at least the second volume, which may convert the polycrystalline material to crystalline material having one or more grains that are larger than one or more grains of the polycrystalline material. The processed ribbon may include a large crystal material or a single crystal material.

What is claimed is: 
     
         1 . A method of manufacturing, comprising:
 heating, using a first heat source, a first volume of a ribbon, the ribbon comprising a polycrystalline material; and   concurrently heating, using a second heat source while the ribbon is moving relative to at least the second heat source and using the first heat source, a second volume of the ribbon that is within the first volume, wherein heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume to a crystalline material comprising one or more grains that are larger than a plurality of grains of the polycrystalline material.   
     
     
         2 . The method of  claim 1 , wherein concurrently heating the second volume using the second heat source comprises:
 heating at least a first surface of the ribbon using the first heat source, wherein heating at least the first surface of the ribbon heats the first volume of the ribbon; and   concurrently heating a second surface of the ribbon different from the first surface, wherein the polycrystalline material is converted to the crystalline material from the first surface of the ribbon and extending to a first depth of the ribbon from the first surface.   
     
     
         3 . The method of  claim 1 , wherein concurrently heating the second volume using the second heat source comprises:
 scanning the second volume of the ribbon with the second heat source while the first volume and the second volume are heated by the first heat source.   
     
     
         4 . The method of  claim 1 , further comprising:
 depositing, before concurrently heating using the first heat source and the second heat source, one or more seed crystals on the polycrystalline material of the ribbon, wherein an orientation of the crystalline material is based at least in part on a shape of the one or more seed crystals, or an orientation of the one or more seed crystals, or both.   
     
     
         5 . The method of  claim 1 , further comprising:
 moving the ribbon relative to the second heat source at a rate that is at least 0.2 inches per minute.   
     
     
         6 . The method of  claim 1 , wherein the first heat source comprises a convection-type heat source, or a first radiation-type heat source, or a combination thereof, for heating at least the first volume, and wherein the second heat source comprises a second radiation-type heat source for irradiating the second volume with photons, the first volume being larger than the second volume. 
     
     
         7 . The method of  claim 1 , wherein the first heat source comprises at least one of a flame, or an oven, or a furnace, or a microwave, and wherein the second heat source comprises at least one of a laser or a focused infrared source. 
     
     
         8 . The method of  claim 1 , further comprising:
 heating the first volume of the ribbon using a third heat source, the first volume comprising a first subset of the polycrystalline material and a second subset of the crystalline material; and   concurrently heating, using a fourth heat source while the ribbon is moving relative to at least the fourth heat source and using the third heat source, the second volume of the ribbon that is within the first volume, wherein heating using the third heat source and the fourth heat source converts at least a portion of the first subset of the polycrystalline material of the ribbon within the second volume to the crystalline material comprising the one or more grains that are larger than the plurality of grains of the polycrystalline material, and wherein a depth of the crystalline material of the ribbon increases based at least in part on concurrently heating using the third heat source and the fourth heat source.   
     
     
         9 . The method of  claim 1 , wherein heating using the first heat source and the second heat source converts at least the portion of the polycrystalline material of the ribbon within the second volume to the crystalline material while the ribbon is in a solid state. 
     
     
         10 . The method of  claim 1 , wherein the polycrystalline material of the ribbon is at least partially sintered.