Seasoning phase change memories

Abstract

A seasoned phase change memory has been subjected to a longer pulse to adjust resistance levels prior to use of the phase change memory.

1 . A method comprising:
 applying a seasoning pulse to a phase change memory cell.   
     
     
         2 . The method of  claim 1  wherein applying a seasoning pulse involves applying a pulse of longer pulse duration than programming pulses to program said cell. 
     
     
         3 . The method of  claim 1  including applying a seasoning pulse to a phase change memory cell including an ovonic threshold switch. 
     
     
         4 . The method of  claim 1  wherein applying a seasoning pulse includes applying a pulse having a pulse duration greater than two microseconds. 
     
     
         5 . The method of  claim 1  wherein applying a seasoning pulse includes applying a pulse having a trapezoidal voltage versus time characteristic. 
     
     
         6 . The method of  claim 5  including applying a seasoning pulse having a leading edge having a duration of less than ten nanoseconds. 
     
     
         7 . The method of  claim 5  including providing a seasoning pulse having a trailing edge less than ten nanoseconds. 
     
     
         8 . The method of  claim 5  including providing a seasoning pulse having a leading edge of more than ten nanoseconds. 
     
     
         9 . The method of  claim 5  including providing a seasoning pulse having a trailing edge of greater than ten nanoseconds. 
     
     
         10 . The method of  claim 5  wherein said seasoning pulse has a leading edge and a trailing edge of substantially the same duration. 
     
     
         11 . The method of  claim 5  wherein said seasoning pulse has a leading edge and a trailing edge of different duration. 
     
     
         12 . The method of  claim 1  including programming said cell with a pulse of shorter duration than said seasoning pulse. 
     
     
         13 . The method of  claim 1  including applying said seasoning pulse during electrical testing. 
     
     
         14 . The method of  claim 1  including creating device current oscillation in response to applying the seasoning pulse. 
     
     
         15 . The method of  claim 1  including applying a second seasoning pulse to said cell. 
     
     
         16 . The method of  claim 1  wherein said seasoning pulse makes the spatial distribution of elements of the phase change material of said phase change memory cell more spatially uniform. 
     
     
         17 . The method of  claim 1  wherein said seasoning pulse modifies the composition of the phase change material of said phase change memory cell adjacent to an electrode of said phase change memory cell. 
     
     
         18 . An apparatus comprising:
 a seasoned chalcogenide; and   a pair of electrodes sandwiching said seasoned chalcogenide.   
     
     
         19 . The apparatus of  claim 18  further including an ovonic threshold switch. 
     
     
         20 . The apparatus of  claim 18  wherein said seasoned chalcogenide is part of an ovonic unified memory. 
     
     
         21 . The apparatus of  claim 20  including an ovonic threshold switch in series with said ovonic unified memory. 
     
     
         22 . The apparatus of  claim 19  including circuitry to produce a seasoning pulse. 
     
     
         23 . A system comprising:
 a processor;   a static random access memory coupled to said processor; and   a phase change memory coupled to said processor, said phase change memory including a seasoned chalcogenide and a pair of electrodes sandwiching said seasoned chalcogenide.   
     
     
         24 . The system of  claim 23  further including an ovonic threshold switch. 
     
     
         25 . The system of  claim 24  including an ovonic threshold switch in series with said ovonic unified memory. 
     
     
         26 . The system of  claim 23  including circuitry to produce a seasoning pulse in said chalcogenide. 
     
     
         27 . A method comprising:
 causing the device current in a phase change memory cell to oscillate.   
     
     
         28 . The method of  claim 27  including causing the current to oscillate by applying a seasoning pulse to the cell. 
     
     
         29 . The method of  claim 27  including causing the cell current to oscillate by applying a trapezoidal pulse to the cell. 
     
     
         30 . The method of  claim 27  including causing the current to oscillate by applying a pulse to the cell having a duration substantially longer than the duration of a programming current pulse.