Chalcogenide devices incorporating chalcogenide materials having reduced germanium or telluruim content

Abstract

A chalcogenide material and chalcogenide memory device having less stringent requirements for formation, improved thermal stability and/or faster operation. The chalcogenide materials include materials comprising Ge, Sb and Te in which the Ge and/or Te content is lean relative to the commonly used Ge<SUB>2</SUB>Sb<SUB>2</SUB>Te<SUB>5 </SUB>chalcogenide composition. Electrical devices containing the instant chalcogenide materials show a rapid convergence of the set resistance during cycles of setting and resetting the device from its as-fabricated state, thus leading to a reduced or eliminated need to subject the device to post-fabrication electrical formation prior to end-use operation. Improved thermal stability is manifested in terms of prolonged stability of the resistance of the device at elevated temperatures, which leads to an inhibition of thermally induced setting of the reset state in the device. Significant improvements in the 10 year data retention temperature are demonstrated. Faster device operation is achieved through an increased speed of crystallization, which acts to shorten the time required to transform the chalcogenide material from its reset state to its set state in an electrical memory device.

1 . A chalcogenide material comprising Ge and a column V element, wherein the atomic concentration of Ge is less than or equal to 20%, and the atomic concentration of said column V element is greater than or equal to 30%.  
     
     
         2 . The chalcogenide material of  claim 1 , wherein the atomic concentration of Ge is less than or equal to 16% and the atomic concentration of said column V element is greater than or equal to 40%.  
     
     
         3 . The chalcogenide material of  claim 1 , wherein the atomic concentration of Ge is less than or equal to 12% and the atomic concentration of said column V element is greater than or equal to 50%.  
     
     
         4 . The chalcogenide material of  claim 1 , wherein said column V element is Sb.  
     
     
         5 . The chalcogenide material of  claim 1 , wherein the atomic concentration of Ge is between 11% and 19%.  
     
     
         6 . The chalcogenide material of  claim 1 , wherein the atomic concentration of Ge is between 13% and 18%.  
     
     
         7 . The chalcogenide material of  claim 1 , wherein the atomic concentration of Ge is between 15% and 17%.  
     
     
         8 . The chalcogenide material of  claim 1 , wherein said material further comprises Te.  
     
     
         9 . The chalcogenide material of  claim 8 , wherein the atomic concentration of Te is less than or equal to 50%.  
     
     
         10 . The chalcogenide material of  claim 8 , wherein the atomic concentration of Te is less than or equal to 40%.  
     
     
         11 . The chalcogenide material of  claim 8 , wherein the atomic concentration of Te is less than or equal to 30%.  
     
     
         12 . The chalcogenide material of  claim 8 , wherein the atomic concentration of Te is between 20% and 50%.  
     
     
         13 . The chalcogenide material of  claim 8 , wherein the atomic concentration of Te is between 30% and 40%.  
     
     
         14 . The chalcogenide material of  claim 8 , wherein the atomic concentration of Te is between 39% and 57.5%.  
     
     
         15 . An electrical device comprising the chalcogenide material of  claim 1 , a first electrode in electrical communication with said chalcogenide material, and a second electrode in electrical communication with said chalcogenide material.  
     
     
         16 . An electrical device comprising a chalcogenide material, a first electrode in electrical communication with said chalcogenide material, and a second electrode in electrical communication with said chalcogenide material, wherein formation of said device in its as-fabricated state requires no more than one electrical pulse for setting said device and one electrical pulse for resetting said device.  
     
     
         17 . The electrical device of  claim 16 , wherein said formation requires no more than one electrical pulse for setting said device.  
     
     
         18 . The electrical device of  claim 16 , wherein said device requires no formation.  
     
     
         19 . An electrical device comprising a chalcogenide material, a first electrode in electrical communication with said chalcogenide material, and a second electrode in electrical communication with said chalcogenide material, said device having: a virgin state, a first set state formed by setting said virgin state, a first reset state formed by resetting said first set state, a second set state formed by setting said first reset state, a second reset state formed by resetting said second set state, and a third set state formed by setting said second reset state, wherein the resistance of said first set state differs from the resistance of said virgin state by less than 50%.  
     
     
         20 . The electrical device of  claim 19 , wherein the resistance of said first set state differs from the resistance of said virgin state by less than 25%.  
     
     
         21 . The electrical device of  claim 19 , wherein the resistance of said first set state differs from the resistance of said virgin state by less than 15%.  
     
     
         22 . The electrical device of  claim 19 , wherein the resistance of said second set state differs from the resistance of said first set state by less than 25%.  
     
     
         23 . The electrical device of  claim 22 , wherein the resistance of said third set state differs from the resistance of said second set state by less than 15%.  
     
     
         24 . The electrical device of  claim 19 , wherein the resistance of said second set state differs from the resistance of said first set state by less than 15%.  
     
     
         25 . An electrical device comprising a chalcogenide material, a first electrode in electrical communication with said chalcogenide material, and a second electrode in electrical communication with said chalcogenide material, wherein the ten-year data retention temperature of the reset state of said device is at least 120° C.  
     
     
         26 . The electrical device of  claim 25 , wherein said ten-year data retention temperature of the reset state of said device is at least 130° C.  
     
     
         27 . The electrical device of  claim 25 , wherein said ten-year data retention temperature of the reset state of said device is at least 140° C.  
     
     
         28 . An electrical device comprising an active chalcogenide material having a volume and shape, a first electrode in electrical communication with said chalcogenide material, and a second electrode in electrical communication with said chalcogenide material, said device having a reset state and a set state, wherein the time required to set said device from its reset state to its set state using an electrical signal is less than or equal to 75% of the time required to set said device with said electrical signal when the active chalcogenide material of said device is Ge 22.2 Sb 22.2 Te 55.5  having said volume and shape.  
     
     
         29 . The electrical device of  claim 28 , wherein said time required to set said device is less than or equal to 50% of said time required to set said device when the active chalcogenide material of said device is Ge 22.2 Sb 22.2 Te 55.5  having said volume and shape.  
     
     
         30 . The electrical device of  claim 28 , wherein said time required to set said device is less than or equal to 30% of said time required to set said device when the active chalcogenide material of said device is Ge 22.2 Sb 22.2 Te 55.5  having said volume and shape.