the present invention discloses a semiconductor source / drain contact structure , which comprises a substrate , a source / drain region disposed in the substrate , at least one non - silicided conductive layer including a barrier layer disposed over and in contact with the source / drain region , and one or more contact hole filling metals disposed over and in contact with the at least one non - silicided conductive layer , wherein a first contact area between the at least one non - silicided conductive layer and the source / drain region is substantially larger than a second contact area between the one or more contact hole filling metals and the at least one non - silicided conductive layer .