Semiconductor devices including silicide regions and methods of fabricating the same

Abstract

A semiconductor device has a silicide source/drain region is fabricated by growing silicon on an epitaxial region including silicon and either germanium or carbon. In the method, a gate electrode is formed on a semiconductor substrate with a gate insulating layer interposed therebetween. An epitaxial layer is formed in the semiconductor substrate at both sides of the gate electrodes. A silicon layer is formed to cap the epitaxial layer. The silicon layer and a metal material are reacted to form a silicide layer. In a PMOS, the epitaxial layer has a top surface and inclined side surfaces that are exposed above the upper surface of the active region. The silicon layer is grown on the epitaxial layer in such a way as to cap the top and inclined surfaces.

What is claimed is: 
     
         1 . A method of fabricating a semiconductor device, comprising:
 forming a gate electrode structure comprising a gate electrode on an active region of a substrate;   forming first and second epitaxial regions in the active region at opposite sides of the gate electrode structure, respectively;   forming a silicon layer on the first and second epitaxial regions including by depositing silicon on each of the first and second epitaxial regions; and   converting at least a portion of the silicon layer, on each of the first and second epitaxial regions, to a silicide.   
     
     
         2 . The method of  claim 1 , wherein the forming of the first and second epitaxial are formed to protrude above the upper surface of the active region. 
     
     
         3 . The method of  claim 1 , wherein the substrate is a silicon substrate, and the forming of the first and second epitaxial regions comprises forming a recess in the substrate at both sides of the gate electrode, and epitaxially growing SiGe in the recess until the SiGe protrudes above an upper surface of the active region, whereby the first and second epitaxial regions each include a top upper surface which is parallel to the upper surface of the active region, and at least one inclined surface which extends downwardly from the upper surface at an inclination relative to the top surface such that the top and inclined surfaces subtend an obtuse angle. 
     
     
         4 . The method of  claim 3 , wherein the silicon layer is formed to cover the top and inclined surfaces of each of the first and second epitaxial regions. 
     
     
         5 . The method of  claim 4 , wherein the silicon layer is formed conformally with respect to the top and inclined surfaces of the epitaxial regions such that the silicon layer has a horizontal portion on the top surface of each of the epitaxial regions and inclined portions on the inclined surfaces of each of the first and second epitaxial regions, respectively. 
     
     
         6 . The method of  claim 4 , wherein the converting of at least a portion of the silicon layer, on each of the first and second epitaxial regions, to a silicide comprises converting the entirety of the silicon layer to a silicide. 
     
     
         7 . The method of  claim 4 , wherein the converting of at least a portion of the silicon layer, on each of the first and second epitaxial regions, to a silicide comprises converting only that portion of the silicon layer located over the top surface of each of the epitaxial regions to silicide. 
     
     
         8 . The method of  claim 4 , wherein the converting of at least a portion of the silicon layer, on each of the first and second epitaxial regions, to a silicide comprises converting only an upper portion of the silicon layer to a silicide such that a portion of the silicon layer remains interposed between the epitaxial regions and the silicide. 
     
     
         9 . The method of  claim 1 , wherein the forming of the first and second epitaxial layers comprises forming silicon-germanium. 
     
     
         10 . The method of  claim 1 , wherein the forming of the first and second epitaxial layers comprises forming silicon-carbon. 
     
     
         11 . The method of  claim 1 , wherein the forming of the silicon layer comprises a selective epitaxial growth process including alternately supplying silicon source gas and selective etch gas into a processing chamber, in which the semiconductor substrate is disposed, as a cycle of operations; and repeating the cycle at least once. 
     
     
         12 . The method of  claim 11 , wherein the silicon source gas comprises at least one of monochlorosilane (SiH 3 Cl), dichlorosilane (DCS), trichlorosilane (TCS), hexachlorosilane (HCS), SiH 4 , and Si 2 H 6 , and the selective etch gas comprises at least one of HCl and Cl 2 . 
     
     
         13 . The method of  claim 1 , wherein the forming of the silicon layer comprises a selective epitaxial growth process including supplying silicon source gas into a process chamber in which the semiconductor substrate is disposed, subsequently purging the process chamber, subsequently supplying selective etch gas into the process chamber, and subsequently purging the process chamber for a second time as a cycle of operations; and repeating the cycle at least once. 
     
     
         14 . The method of  claim 13 , wherein the silicon source gas comprises at least one of monochlorosilane (SiH 3 Cl), dichlorosilane (DCS), trichlorosilane (TCS), hexachlorosilane (HCS), SiH 4 , and Si 2 H 6 , and the selective etch gas comprises at least one of HCl and Cl 2 .