Resistance change memory and forming method of the resistance change device

Abstract

A resistance change memory has a resistance change device and a control circuit for controlling application of voltage to the resistance change device. The resistance change device has a first electrode, a second electrode, and a resistance change layer interposed between the first electrode and the second electrode. A material for the second electrode includes one of members selected from the group consisting of W, Ti, Ta, and nitrides thereof. During forming of the resistance change device, the control circuit performs a second forming treatment succeeding to a first forming treatment. The first forming treatment includes application of voltage such that the potential of the first electrode is higher than the potential of the second electrode. The second forming treatment includes application of voltage such that the potential of the second electrode is higher than the potential of the first electrode.

What is claimed is: 
     
         1 . A resistance change memory comprising:
 a resistance change device including a first electrode, a second electrode, and a resistance change layer interposed between the first electrode and the second electrode; and   a control circuit configured to perform a first forming treatment to form an initial first portion of a filament between the first electrode and the second electrode and then a second forming treatment to form an initial second portion of the filament.   
     
     
         2 . The resistance change memory according to  claim 1 , wherein the initial second portion electrically connects the initial first portion to the second electrode. 
     
     
         3 . The resistance change memory according to  claim 1 , wherein the filament formed by the initial first portion and the initial second portion electrically connects the first electrode to the second electrode. 
     
     
         4 . The resistance change memory according to  claim 1 , wherein the first forming treatment includes application of voltage such that the potential of the first electrode is higher than the potential of the second electrode, and the second forming treatment includes application of voltage such that the potential of the second electrode is higher than the potential of the first electrode. 
     
     
         5 . The resistance change memory according to  claim 4 , wherein the first forming treatment further includes application of voltage such that the potential on the second electrode is higher than the potential on the first electrode. 
     
     
         6 . A resistance change memory comprising:
 a resistance change device including a first electrode, a second electrode, and a resistance change layer interposed between the first electrode and the second electrode; and   a control circuit configured to perform an initial first forming treatment to form a first portion of the resistance change device and then an initial second forming treatment to form a second portion of the resistance change device,   wherein the first forming treatment includes application of voltage such that the potential of the first electrode is higher than the potential of the second electrode, and the second forming treatment includes application of voltage such that the potential of the second electrode is higher than the potential of the first electrode.   
     
     
         7 . The resistance change memory according to  claim 6 , wherein the second portion electrically connects the first portion to the second electrode. 
     
     
         8 . The resistance change memory according to  claim 6 , wherein the first portion and the second portion of the resistance change device together form a filament that electrically connects the first electrode to the second electrode. 
     
     
         9 . The resistance change memory according to  claim 6 , wherein the first forming treatment further includes application of voltage such that the potential on the second electrode is higher than the potential on the first electrode. 
     
     
         10 . A resistance change memory comprising:
 a resistance change device including a first electrode, a second electrode, and a resistance change layer interposed between the first electrode and the second electrode; and   a control circuit configured to create a two-part filament in the resistance change layer that electrically connects the first electrode and the second electrode by performing a first forming treatment to form a first part of the two-part filament and performing a second forming treatment different from the first forming treatment to form a second part of the two-part filament.   
     
     
         11 . The resistance change memory according to  claim 10 , wherein the control circuit is configured to form the second part of the two-part filament after the first part of the two-part filament is already formed. 
     
     
         12 . The resistance change memory according to  claim 10 , wherein, prior to the control circuit forming the two-part filament, there is no filament in the resistance change layer. 
     
     
         13 . The resistance change memory according to  claim 10 , wherein the second part of the two-part filament electrically connects the first part of the two-part filament to the second electrode. 
     
     
         14 . The resistance change memory according to  claim 10 , wherein the first forming treatment includes application of voltage such that the potential of the first electrode is higher than the potential of the second electrode, and the second forming treatment includes application of voltage such that the potential of the second electrode is higher than the potential of the first electrode.