Epitaxial wafer manufacturing method and epitaxial wafer

Abstract

Provided is an epitaxial wafer having an excellent gettering capability and a suppressed formation of epitaxial defects. The epitaxial wafer has a specified resistivity, and includes a modifying layer formed on a surface portion of the silicon wafer and composed of a predetermined element including at least carbon, in the form of a solid solution in the silicon wafer; and an epitaxial layer having a resistivity that is higher than the resistivity of the silicon wafer, wherein a concentration profile of the predetermined element in the modifying layer in a depth direction thereof meets a specified full width half maximum and a specified peak concentration.

The invention claimed is: 
     
       1. An epitaxial wafer, comprising:
 a silicon wafer having a resistivity adjusted to a range of from 0.001 Q·cm to 0.1 Q·cm to thereby suppress formation of defects in an epitaxial layer of the wafer; and substrate having a surface and a surface portion, the surface portion having a depth from the surface of the silicon substrate, the silicon substrate having a first resistivity of from 0.001 Ω·cm to 0.1 Ω·cm; 
 a modifying layer formed in a the surface portion of the silicon wafer and substrate, the modifying layer composed of a at least one predetermined element including at least carbon, in the form of a solid solution in the silicon wafer; and 
 an epitaxial layer formed on the surface, the epitixial layer having a second resistivity that is higher than the resistivity of the silicon wafer, wherein first resistivity; 
 wherein a concentration profile of the at least one predetermined element in the modifying layer, in a depth direction thereof, has a full width half maximum of 100 nm or less, and the concentration profile in the modifying layer further has a peak concentration of from 9.0×10 18  atoms/cm 3  to 1.0×10 21  atoms/cm 3 , and wherein the such peak concentration profile in the modifying layer has a peak located in the range at a depth of being located within 150 nm or less from a from the surface of the silicon wafer substrate. 
 
     
     
       2. The epitaxial wafer according to  claim 1 , wherein the predetermined element comprises two or more elements including carbon. 
     
     
       3. The epitaxial wafer according to  claim 1 , wherein the resistivity of the silicon wafer is adjusted by addition of boron. 
     
     
       4. The epitaxial wafer according to  claim 2 , wherein the resistivity of the silicon wafer is adjusted by addition of boron. 
     
     
       5. The epitaxial wafer of claim 1, wherein the first resistivity is sufficiently low as to suppress formation of defects in the epitaxial layer. 
     
     
       6. The epitaxial wafer of claim 2, wherein the at least one predetermined element further includes boron. 
     
     
       7. The epitaxial wafer of claim 1, wherein the concentration profile in the modifying layer is measured after formation of the epitaxial layer. 
     
     
       8. An epitaxial wafer comprising:
 a silicon substrate having a surface and a surface portion, the surface portion having a depth from the surface of the silicon substrate, the silicon substrate having a first resistivity of from 0.001 Ω·cm to 0.1 Ω·cm;   a modifying layer formed in the surface portion of the silicon substrate, the modifying layer composed of at least carbon in the form of a solid solution; and   an epitaxial layer formed on the surface, the epitaxial layer having a second resistivity that is higher than the first resistivity;   wherein a concentration profile of carbon in the modifying layer, in a depth direction thereof, has a full width half maximum of 100 nm or less, and the concentration profile further has a peak concentration between 9.0×10 18  atoms/cm 3  to 1.0×10 21  atoms/cm 3 , and such peak concentration being located within 150 nm from the surface of the silicon substrate.   
     
     
       9. The epitaxial wafer of claim 8, wherein the first resistivity is sufficiently low as to suppress formation of defects in the epitaxial layer. 
     
     
       10. The epitaxial wafer of claim 8, wherein the modifying layer further comprises boron. 
     
     
       11. The epitaxial wafer of claim 8, wherein the concentration profile in the modifying layer is measured after formation of the epitaxial layer. 
     
     
       12. An epitaxial wafer comprising:
 a silicon substrate having a surface and a surface portion, the surface portion having a depth from the surface of the silicon substrate, the silicon substrate having a first resistivity of from 0.001 Ω·cm to 0.1 Ω·cm;   a modifying layer formed in the surface portion of the silicon substrate, the modifying layer composed of at least a predetermined element in the form of a solid solution; and   an epitaxial layer formed on the surface, the epitaxial layer having a second resistivity that is higher than the first resistivity;   wherein a concentration profile of predetermined element in the modifying layer, in a depth direction thereof, has a full width half maximum of 100 nm or less, and the concentration profile further has a peak concentration between 9.0×10 18  atoms/cm 3  to 1.0×10 21  atoms/cm 3 , and such peak concentration being located within 150 nm from the surface of the silicon substrate;   wherein the peak concentration suppresses diffusion of dopants and/or oxygen from the silicon substrate into the epitaxial layer.   
     
     
       13. The epitaxial wafer of claim 10, wherein the at least one predetermined element includes carbon. 
     
     
       14. The epitaxial wafer of claim 12, wherein the first resistivity is sufficiently low as to suppress formation of defects in the epitaxial layer. 
     
     
       15. The epitaxial wafer of claim 12, wherein the at least one predetermined element further includes boron. 
     
     
       16. The epitaxial wafer of claim 12, wherein the concentration profile in the modifying layer is measured after formation of the epitaxial layer.