Forming heaters for phase change memories

Abstract

A heater for a phase change memory may be thrilled by depositing a first material into a trench such that the material is thicker on the side wall than on the bottom of the trench. In one embodiment, because the trench side walls are of a different material than the bottom, differential deposition occurs. Then a heater material is deposited thereover. The heater material may react with the first material at the bottom of the trench to make Ohmic contact with an underlying metal layer. As a result, a vertical heater may be formed which is capable of making a small area contact with an overlying chalcogenide material.

What is claimed is: 
     
         1 . An apparatus comprising:
 a substrate;   a vertical wall defined over the substrate:   a material formed on the vertical wall; and   a heater material including a horizontal portion formed in contact with the substrate and a vertical portion formed in contact with the material.   
     
     
         2 . The apparatus of  claim 1 , wherein the substrate is formed of metal and the vertical wall is formed in a dielectric. 
     
     
         3 . The apparatus of  claim 2 , further comprising a layer of the material formed over the heater material. 
     
     
         4 . The apparatus of  claim 1 , wherein the material includes boron. 
     
     
         5 . An apparatus comprising:
 a metal material;   a heater including a horizontal portion formed adjacent to the metal material and a vertical portion formed between two columns of a material, wherein the vertical portion of the heater contacts the material of the two columns.   
     
     
         6 . The apparatus of  claim 5 , wherein the material comprises boron. 
     
     
         7 . The apparatus of  claim 5 , farther comprising a phase change material defined over the vertical portion and the two columns of the material. 
     
     
         8 . The apparatus of  claim 7 , wherein the phase change material comprises a chalcogenide material. 
     
     
         9 . The apparatus of  claim 7 , wherein the phase change material has a first resistance in a first state and a second resistance in at second state. 
     
     
         10 . The apparatus of  claim 5 , wherein the metal material is coupled to a address line. 
     
     
         11 . An apparatus comprising:
 a plurality of phase change memory (PCM) cells, wherein a PCM cell of the plurality of PCM cells comprises a substrate, a heater, and a chalocogenide material, wherein a first portion of the heater contacts the substrate and a second portion of the heater contacts the chalcogenide material, wherein the second portion of the beater is formed between a first layer of a first material and a second layer of a second material, wherein the second portion of the heater contacts the first layer and the second layer, wherein the first material and the second material each comprise boron.   
     
     
         12 . The apparatus of  claim 11 , wherein the first material is the same material as the second material. 
     
     
         13 . The apparatus of  claim 11 , wherein each PCM cell of the plurality of PCM cells comprises a dot of the chalcogenide material. 
     
     
         14 . The apparatus of  claim 13 , wherein a first subset of the plurality of PCM cells comprises the substrate, wherein the first subset of the plurality of PCM cells forms a line defined by the substrate. 
     
     
         15 . The apparatus of  claim 14 , wherein the substrate comprises a first conductive line. 
     
     
         16 . The apparatus of  claim 15 , wherein the dot of the chalcogenide material is coupled to a second conductive line that extends transversely to a length of the first conductive line, wherein a second subset of the plurality of PCM cells forms a line defined by the second conductive line that is perpendicular to the first conductive line. 
     
     
         17 . The apparatus of  claim 16 , wherein the first conductive line and the second conductive line each comprise a metallic material. 
     
     
         18 . The apparatus of  claim 11 , wherein the chalcogenide material of the PCM cell is configured to have a first resistance in a first state and a second resistance in the second state. 
     
     
         19 . The apparatus of  claim 11 , wherein the first layer contacts a dielectric material. 
     
     
         20 . A memory cell comprising:
 a heater between a metal material and a phase-change material, wherein the heater comprises a vertical portion and a horizontal portion, wherein the horizontal portion of the heater is in physical contact with the metal material, and wherein a layer of a material is between the vertical portion of the heater and a vertical wall.   
     
     
         21 . The memory cell of  claim 20  wherein as contact between the horizontal portion of the heater and the metal material is devoid of the material. 
     
     
         22 . The memory cell of  claim 20 , wherein the material includes boron. 
     
     
         23 . The memory cell of  claim 20 , further comprising a capping layer of a second material, wherein the vertical portion of the heater is between the layer of the material and the capping layer of the second material. 
     
     
         24 . The memory cell of  claim 23 , wherein the vertical portion of the heater contacts the layer of the material and contacts the capping layer of the second material. 
     
     
         25 . The memory cell of  claim 23 , wherein the material and the second material each include boron.