Elimination of dendrite formation during metal/chalcogenide glass deposition

Abstract

A method of forming a programmable conductor memory cell array is disclosed wherein metal and chalcogenide glass are co-sputtered to fill an array of cell vias in a prepared substrate. The prepared substrate is heated above room temperature before the metal and chalcogenide glass film is deposited, and the heating is maintained throughout the deposition. The resulting metal/chalcogenide glass film has good homogeneity, a desired ratio of components, and has a regular surface.

We claim:  
     
         1 . A method of forming a programmable conductor memory cell comprising: 
 sputtering metal and chalcogenide glass onto a prepared substrate; and    maintaining the prepared substrate at a temperature higher than room temperature during the sputtering.    
     
     
         2 . The method of  claim 1 , wherein sputtering metal and chalcogenide glass comprises first sputtering a chalcogenide glass element and then separately sputtering a metal layer thereover.  
     
     
         3 . The method of  claim 1 , wherein sputtering metal and chalcogenide glass comprises co-sputtering.  
     
     
         4 . The method of  claim 1 , wherein the prepared substrate comprises a top insulating layer with vias therein.  
     
     
         5 . The method of  claim 1 , wherein the programmable conductor memory cell comprises metal and chalcogenide glass containing between about 25% and 35% metal.  
     
     
         6 . The method of  claim 1 , wherein the metal is a fast diffuser.  
     
     
         7 . The method of  claim 1 , wherein the metal is silver.  
     
     
         8 . The method of  claim 1 , wherein the metal is copper.  
     
     
         9 . The method of  claim 1 , wherein the chalcogenide glass comprises components selected from the group consisting of sulfur, germanium, selenium, and tellurium.  
     
     
         10 . The method of  claim 1 , wherein the chalcogenide glass comprises germanium selenide.  
     
     
         11 . The method of  claim 1 , further comprising maintaining the prepared substrate at a temperature higher than room temperature for at least 5 minutes before sputtering the metal and chalcogenide glass.  
     
     
         12 . The method of  claim 1 , wherein maintaining the prepared substrate at a temperature higher than room temperature comprises maintaining the prepared substrate at between about 30° C. and 150° C.  
     
     
         13 . The method of  claim 1 , wherein maintaining the prepared substrate at a temperature higher than room temperature comprises maintaining the prepared substrate at between about 45° C. and 60° C.  
     
     
         14 . A method of co-sputtering a homogeneous metal/chalcogenide glass layer onto an irregular surface, comprising keeping the irregular surface at an elevated temperature, above room temperature, before and during the co-sputtering.  
     
     
         15 . The method of  claim 14 , wherein the metal/chalcogenide glass layer comprises silver, germanium, and selenium.