Method for fabricating schottky device

Abstract

A method for fabricating a Schottky device includes the following sequences. First, a substrate with a first conductivity type is provided and an epitaxial layer with the first conductivity type is grown on the substrate. Then, a patterned dielectric layer is formed on the epitaxial layer, and a metal silicide layer is formed on a surface of the epitaxial layer. A dopant source layer with a second conductivity type is formed on the metal silicide layer, followed by applying a thermal drive-in process to diffuse the dopants inside the dopant source layer into the epitaxial layer. Finally, a conductive layer is formed on the metal silicide layer.

What is claimed is: 
     
         1 . A fabricating method of a Schottky device, comprising:
 providing a substrate having a first conductivity type;   forming an epitaxial layer on the substrate, wherein the epitaxial layer has the first conductivity type;   forming a patterned dielectric layer on the epitaxial layer;   forming a guard ring of a second conductivity type in the epitaxial layer;   forming a silicide layer on a surface of the epitaxial layer, wherein the silicide layer covers the guard ring;   forming a dopant source layer on the silicide layer, wherein the dopant source layer has a plurality of dopants with the second conductivity type;   performing a thermal drive-in process to diffuse the dopants from the dopant source layer into the epitaxial layer through the silicide layer, thereby forming a doped region of the second conductivity type; and   forming a conductive layer on the silicide layer.   
     
     
         2 . The fabricating method of the Schottky device according to  claim 1 , wherein the surface of the epitaxial layer comprises at least a lattice defect structure. 
     
     
         3 . The fabricating method of the Schottky device according to  claim 2 , wherein the lattice defect structure comprises seam defects, void defects, or lattice dislocations. 
     
     
         4 . The fabricating method of the Schottky device according to  claim 2 , wherein the doped region encompasses the lattice defect structure. 
     
     
         5 . The fabricating method of the Schottky device according to  claim 4 , wherein a doping concentration of dopants with the second conductivity type in the doped region ranges from 1e14 atoms/cm3 to 1e19 atoms/cm3. 
     
     
         6 . The fabricating method of the Schottky device according to  claim 1 , further comprising:
 forming a buffer layer on the silicide layer before forming the dopant source layer.   
     
     
         7 . The fabricating method of the Schottky device according to  claim 6 , further comprising:
 removing the dopant source layer and the buffer layer after performing the thermal drive-in process.   
     
     
         8 . The fabricating method of the Schottky device according to  claim 7 , wherein the buffer layer comprises silicon oxide. 
     
     
         9 . The fabricating method of the Schottky device according to  claim 1 , wherein the first conductivity type is N-type and the second conductivity type is P-type. 
     
     
         10 . The fabricating method of the Schottky device according to  claim 1 , wherein the silicide layer comprises titanium silicide (TiSi 2 ), nickel silicide (NiSi), platinum silicide (PtSi), molybdenum silicide (MoSi 2 ), or cobalt silicide (CoSi 2 ). 
     
     
         11 . The fabricating method of the Schottky device according to  claim 1 , wherein the dopant source layer comprises monocrystalline silicon, polycrystalline silicon, amorphous silicon, or borosilicate glass (BSG). 
     
     
         12 . The fabricating method of the Schottky device according to  claim 1 , wherein the dopants of the second conductivity type comprises boron atoms. 
     
     
         13 . The fabricating method of the Schottky device according to  claim 1 , wherein the thermal drive-in process comprises rapid thermal process (RTP), spike thermal annealing, laser thermal annealing (LTA), or laser spike annealing, (LSA). 
     
     
         14 . The fabricating method of the Schottky device according to  claim 1 , wherein the conductive layer comprises titanium, nickel, gold, aluminum, or a combination thereof.