Phase change memory stack with treated sidewalls
Memory devices and methods for fabricating memory devices have been disclosed. One such method includes forming the memory stack out of a plurality of elements. An adhesion species is formed on at least one sidewall of the memory stack wherein the adhesion species has a gradient structure that results in the adhesion species intermixing with an element of the memory stack to terminate unsatisfied atomic bonds of the element. The gradient structure further comprises a film of the adhesion species on an outer surface of the at least one sidewall. A dielectric material is implanted into the film of the adhesion species to form a sidewall liner.
1. A method of fabricating a memory stack, comprising:
forming the memory stack comprising multiple stacked elements, the memory stack defined in part by sidewalls;
forming an adhesion species on at least one sidewall of the memory stack, including intermixing the adhesion species with an element of the memory stack, and further including forming a film of the adhesion species on an outer surface of the intermixed adhesion species; and
implanting a dielectric material into the adhesion species film.
2. The method of claim 1 , wherein intermixing the adhesion species with the element comprises implanting the adhesion species into the sidewall of the element.
3. The method of claim 2 , wherein implanting the adhesion species into the sidewall of the element comprises performing a plasma doping process at an energy less than 3 keV.
4. The method of claim 1 , wherein implanting the dielectric material into the adhesion species film comprises a plasma doping process at an energy within the range of 0-2 keV.
5. The method of claim 1 , wherein forming the adhesion species comprises performing both a plasma doping process and a deposition process.
6. The method of claim 5 , wherein performing the plasma doping process comprises performing a plasma doping of boron into the sidewall of the element of the memory stack.
7. The method of claim 6 , wherein implanting the dielectric material into the film comprises implanting a nitride forming material into the film to form a boron and nitride (BN X ) dielectric film.
8. The method of claim 1 , wherein forming the memory stack comprising forming multiple stacked elements comprising:
forming a word line material;
forming a first electrode material over the word line material;
forming a variable resistance material over the second electrode material; and
forming a second electrode material over the phase change material.
9. The method of claim 8 , wherein at east one of the first and second electrode materials includes carbon.
10. The method of claim 9 , wherein the boron adhesion species terminates unsatisfied atomic bonds of the carbon.
11. The method of claim 8 , wherein forming the word line material comprises forming a material including tungsten.
12. A method for fabricating a memory device comprising:
forming multiple memory stacks defined in part by sidewalls, each memory stack fabricated by:
forming a first electrode over a word line material;
forming a variable resistance material over the first electrode;
forming a second electrode over the variable resistance material; and
patterning and etching the first and second electrodes and the variable resistance material to form the multiple memory stacks;
forming an adhesion species on at least one sidewall of each of multiple memory stacks using a doping process and a deposition process, wherein the adhesion species comprises a first portion implanted to intermix with at least one element of the memory stack, and a second portion comprising a film of the adhesion species over the first portion; and
forming a liner material on the sidewalls of multiple memory stacks by implanting a dielectric material into the film of the adhesion species.
13. The method of claim 12 , wherein forming the adhesion species comprises forming a gradient structured adhesion species on the sidewalls, comprising:
using a plasma doping process to implant a boron species; and
using a deposition process to form a boron film on the sidewall over the implanted boron species.
14. The method of claim 12 , wherein forming the liner material comprises forming a boron and nitride (BN X ) liner material over at least one of the first and second electrodes.
15. The method of claim 12 , further comprising forming a dielectric fill material between pairs of the memory stacks.
16. The method of claim 12 , wherein forming the liner material comprises forming the liner material through a plasma doping process at a temperature of less than 390□ C.