Process for transferring a thin layer to a support substrate that have different thermal expansion coefficients

Abstract

A process for transferring a thin layer consisting of a first material to a support substrate consisting of a second material having a different thermal expansion coefficient, comprises providing a donor substrate composed of an assembly of a thick layer formed of the first material and of a handle substrate having a thermal expansion coefficient similar to that of the support substrate, and the donor substrate having a main face on the side of the thick laver; introducing light species into the thick layer to generate a plane of weakness therein and to define the thin layer between the plane of weakness and the main face of the donor substrate; assembling the main face of the donor substrate with a face of the support substrate; and detachment of the thin layer at the plane of weakness, the detachment comprising application of a heat treatment.

What is claimed is: 
     
         1 . A donor substrate comprising:
 a source substrate bonded to a handle substrate along an interface, wherein a coefficient of thermal expansion of the source substrate is different than a coefficient of thermal expansion of the handle substrate; and   an embrittlement plane comprising at least one light species within the source substrate, the embrittlement plane delimiting a thin layer between the embrittlement plane and a surface of the source substrate opposite the interface between the source substrate and the handle substrate.   
     
     
         2 . The donor substrate of  claim 1 , further comprising at least one adhesion layer between the source substrate and the handle substrate. 
     
     
         3 . The donor substrate of  claim 2 , wherein the at least one adhesion layer comprises one or more of silicon oxide and silicon nitride. 
     
     
         4 . The donor substrate of  claim 1 , wherein the source substrate has a thickness between 5 microns and 400 microns. 
     
     
         5 . The donor substrate of  claim 1 , wherein the at least one light species comprises one or more of hydrogen ions and helium ions. 
     
     
         6 . The donor substrate of  claim 1 , wherein the thin layer has a thickness of between 200 nm to 2000 nm. 
     
     
         7 . The donor substrate of  claim 1 , wherein the coefficient of thermal expansion of the source substrate differs from the coefficient of thermal expansion of handle substrate by at least 10% at room temperature. 
     
     
         8 . The donor substrate of  claim 1 , wherein the source substrate comprises a ferroelectric material and the handle substrate comprises silicon. 
     
     
         9 . An assembly comprising:
 a donor substrate comprising a first material bonded to a handle substrate, wherein a coefficient of thermal expansion of the first material is different than a coefficient of thermal expansion of the handle substrate;   a support substrate attached to the first material of the donor substrate, wherein a coefficient of thermal expansion of the support substrate is different than a coefficient of thermal expansion of the first material; and   an embrittlement plane comprising at least one light species within the first material, the embrittlement plane delimiting a thin layer of the first material between the embrittlement plane and the support substrate.   
     
     
         10 . The assembly of  claim 9 , further comprising at least one intermediate layer between the donor substrate and the support substrate. 
     
     
         11 . The assembly of  claim 10 , wherein the at least one intermediate layer comprises silicon oxide, silicon nitride, or polycrystalline silicon. 
     
     
         12 . The assembly of  claim 9 , wherein an absolute value difference between the coefficient of thermal expansion of the handle substrate and the coefficient of thermal expansion of the support substrate is less than an absolute value difference between the coefficient of thermal expansion of the first material and the coefficient of thermal expansion of the support substrate. 
     
     
         13 . The assembly of  claim 9 , wherein the coefficient of thermal expansion of the handle substrate is equal to the coefficient of thermal expansion of the support substrate. 
     
     
         14 . The assembly of  claim 9 , wherein a thickness of the handle substrate is substantially equal to a thickness of the support substrate. 
     
     
         15 . The assembly of  claim 9 , wherein the support substrate comprises silicon, sapphire, or glass. 
     
     
         16 . A donor substrate comprising:
 a ferroelectric material bonded to a handle substrate, wherein a coefficient of thermal expansion of the handle substrate is different than a coefficient of thermal expansion of the handle substrate; and   an embrittlement plane comprising at least one light species implanted in the ferroelectric material, the embrittlement plane delimiting a thin layer of the ferroelectric material between the at least one light species and a main face of the donor substrate.   
     
     
         17 . The donor substrate of  claim 16 , wherein the ferroelectric material is selected from the group consisting of LiTaO 3 , LiNbO 3 , LiAlO 3 , BaTiO 3 , PbZrTiO 3 , KNbO 3 , BaZrO 3 , CaTiO 3 , PbTiO 3 , and KTaO 3 . 
     
     
         18 . The donor substrate of  claim 16 , wherein the ferroelectric material is bonded by molecular adhesion to the handle substrate. 
     
     
         19 . The donor substrate of  claim 16 , wherein the handle substrate comprises silicon, sapphire, or glass. 
     
     
         20 . The donor substrate of  claim 16 , wherein the coefficient of thermal expansion of the handle substrate is about 2.6×10 −6  K −1 .