Multilevel phase-change memory element and operating method

Abstract

A multilevel phase-change memory, operating method and manufacturing method thereof. The phase-change memory includes two phase-change layers and electrodes, which are configured in a parallel structure to form a memory cell. A voltage-drive mode is employed to control and drive the memory such that multilevel memory states may be achieved by imposing different voltage levels. The provided multilevel phase-change memory has more bits and higher capacity than that of the memory with a single phase-change layer.

1 - 15 . (canceled)  
     
     
         16 . A manufacture method for fabricating a phase change memory comprising: 
 providing a substrate, in which a metal contact is formed;    forming a bottom electrode on the substrate;    forming a phase change layer on the bottom electrode;    implanting ions on one portion of the phase change layer to form a first phase change layer a second phase change layer; and    forming a first top electrode a second top electrode on the corresponding first phase change layer and second phase change layer.    
     
     
         17 . The manufacture method of  claim 16  further comprises a step of etching the bottom electrode and the phase change layer.  
     
     
         18 . The manufacture method of  claim 16 , wherein the element for the ion implanting is one selected from the group consisting of III A group, IVA group, VA group, VIA group and rare-earth transition metals.  
     
     
         19 . The manufacture method of  claim 16  further comprises a step of etching the first phase change layer and the second phase change layer to separate the first phase change layer and the second phase change layer.  
     
     
         20 . The manufacture method of  claim 16 , wherein a function layer is formed before forming the first top electrode; wherein the function layer is one or any combination of a heating layer for increasing heating efficiency, a nucleation accelerating layer for accelerating crystallization speed of the first phase change layer, diffusion stop layer for preventing diffusion between the first phase change layer and the first top electrode.  
     
     
         21 . The manufacture method of  claim 16 , wherein a function layer is formed before forming the second top electrode; wherein the function layer is one or any combination of a heating layer for increasing heating efficiency, a nucleation accelerating layer for accelerating crystallization speed of the second phase change layer, diffusion stop layer for preventing diffusion between the second phase change layer and the second top electrode.  
     
     
         22 . A manufacture method for fabricating a phase change memory comprising: 
 providing a substrate, in which a metal contact is formed;    forming a bottom electrode on the substrate;    forming a first phase change layer a second phase change layer on the bottom electrode; and    forming a first top electrode a second top electrode on the corresponding first phase change layer and second phase change layer.    
     
     
         23 . The manufacture method of  claim 22 , wherein a function layer is formed before forming the first top electrode; wherein the function layer is one or any combination of a heating layer for increasing heating efficiency, a nucleation accelerating layer for accelerating crystallization speed of the first phase change layer, diffusion stop layer for preventing diffusion between the first phase change layer and the first top electrode.  
     
     
         24 . The manufacture method of  claim 22 , wherein a function layer is formed before forming the second top electrode; wherein the function layer is one or any combination of a heating layer for increasing heating efficiency, a nucleation accelerating layer for accelerating crystallization speed of the second phase change layer, diffusion stop layer for preventing diffusion between the second phase change layer and the second top electrode.  
     
     
         25 - 26 . (canceled)