Phase-change memory device and method of fabricating the same

Abstract

A phase-change memory device includes a lower electrode; and at least two phase-change memory cells sharing the lower electrode. Another phase-change memory device includes a heating layer having a smaller contact area with a phase-change material layer and a greater contact area with a PN diode structure.

1 . A method of fabricating a phase-change memory device, the method comprising:
 forming a lower electrode comprising a PN diode structure including a junction of an N-type conductive layer and a P-type conductive layer;   forming a plurality of heating elements on an upper one of the P-type conductive layer and the N-type conductive layer;   selectively etching the upper one of the P-type conductive layer and the N-type conductive layer between the heating elements;   forming a separated phase-change material layer on each of the heating elements; and   forming a separated upper electrode on each phase-change material layer.   
     
     
         2 . The method of  claim 1 , wherein each heating element is formed in a plug type, a cup type or a cylinder type. 
     
     
         3 . The method of  claim 2 , wherein the heating element is formed in the plug type by:
 forming an insulating layer having an open region that exposes the top of the upper one of the P-type conductive layer and the N-type conductive layer; and   filling the open region with a conductive material to obtain the heating element.   
     
     
         4 . The method of  claim 2 , wherein the heating element is formed in the cup type by:
 forming an insulating layer having an open region that exposes the top of the upper one of the P-type conductive layer and the N-type conductive layer;   forming a conductive layer over the insulating layer including the open region; and   removing the conductive layer outside the open region.   
     
     
         5 . The method of  claim 2 , wherein the phase-change material layer is formed to cover only a portion of the respective heating element. 
     
     
         6 . The method of  claim 1 , wherein each of the N-type conductive layer and the P-type conductive layer is formed of a silicon layer.