Method of fabricating a composite structure with a stable bonding layer of oxide

Abstract

A method of fabricating a composite structure that has at least one thin film bonded to a support substrate and a bonding layer of oxide formed by deposition between the support substrate and the thin film. The thin film and the support substrate have a mean thermal expansion coefficient of 7×10 −6 K −1 or more. The bonding layer of oxide is formed by low pressure chemical vapor deposition (LPCVD) of a layer of oxide on the bonding face of the support substrate or on the bonding face of the thin film. The thin film has a thickness of 5 micrometers or less while the thickness of the layer of oxide is equal to or greater than the thickness of the thin film.

1 .- 16 . (canceled) 
   
   
       17 . A method of fabricating a composite structure comprising at least one thin film bonded to a support substrate, a bonding layer of oxide formed between the support substrate and the thin film by deposition, with the thin film and the support substrate having a mean thermal expansion coefficient of 7×10 −6  K −1  or more, wherein the bonding layer of oxide is formed by low pressure chemical vapor deposition (LPCVD) of a layer of oxide on either a bonding face of the support substrate or a bonding face of the thin film, or both, wherein the thin film has a thickness of 5 micrometers or less and the bonding layer of oxide has a thickness that is equal to or greater than the thickness of the thin film. 
   
   
       18 . The method of  claim 17 , wherein the layer of oxide is an oxide of silicon formed using precursors of silane, dichlorosilane or tetra-ethyl orthosilicate. 
   
   
       19 . The method of  claim 17 , which further comprises, prior to bonding, conducting a densification heat treatment of the layer of oxide. 
   
   
       20 . The method of  claim 19 , wherein the densification heat treatment step is carried out at a temperature that is higher than the temperature at which the bonding layer of oxide is deposited. 
   
   
       21 . The method of  claim 17 , wherein the thin film is transferred to the support substrate by:
 implanting ions by bombardment of a face of the donor substrate to form, at a predetermined depth in the donor substrate, a layer of weakness defining the thin film between the donor substrate face and the layer of weakness;   placing the donor substrate face of in intimate contact with the support substrate to bond the two together; and   detaching the thin film splitting at the layer of weakness of the donor substrate.   
   
   
       22 . The method of  claim 17 , wherein the thin film is transferred to the support substrate by:
 bringing one face of a donor substrate into intimate contact with the support substrate to bond the two together; and   thinning the donor substrate to leave only the thin film on the support substrate.   
   
   
       23 . The method of  claim 22 , which further comprises, after the bonding step, conducting a bonding stabilization annealing at a temperature of more than approximately 900° C. 
   
   
       24 . The method of  claim 17 , wherein the thin film is approximately 0.3 micrometers thick. 
   
   
       25 . The method of  claim 17 , wherein the bonding oxide layer is approximately 0.4 micrometers thick. 
   
   
       26 . The method of  claim 17 , wherein the support substrate comprises sapphire, LiTaO3, LiNbO3, MgO, or an alloy of Ni, Cr, Mo and W. 
   
   
       27 . The method of  claim 17 , wherein the thin film comprises sapphire, LiTaO3, LiNbO3, or MgO. 
   
   
       28 . A method of producing at least one layer of semiconductor material, by epitaxial growth of the at least one layer of semiconductor material on a composite structure that is made according to the method of  claim 17 , wherein the epitaxial growth is carried out on the thin film of the composite structure. 
   
   
       29 . The method of  claim 28 , wherein the layer of epitaxially grown semiconductor material is a layer of a binary, ternary, or quaternary III/N material. 
   
   
       30 . The method of  claim 28 , wherein the epitaxial growth is carried out for a predetermined period corresponding to the formation of a thickness of semiconductor material or a cumulative thickness of the semiconductor material layer and the thin film of at least 10 micrometers. 
   
   
       31 . A multilayer structure comprising a composite structure made according to the method of  claim 17 . 
   
   
       32 . The structure of  claim 31 , further comprising at least one layer of semiconductor material on the thin film of the composite structure. 
   
   
       33 . A composite structure comprising at least one thin film bonded to a support substrate, a bonding layer of oxide between the support substrate and the thin film, with the thin film and the support substrate having a mean thermal expansion coefficient of 7×10 −6  K −1  or more, wherein the thin film has a thickness of 5 micrometers or less and the bonding layer of oxide has a thickness that is equal to or greater than the thickness of the thin film. 
   
   
       34 . The structure of  claim 33 , further comprising at least one layer of semiconductor material on the thin film of the composite structure.