Buried low-resistance metal word lines for cross-point variable-resistance material memories
Variable-resistance material memories include a buried salicide word line disposed below a diode. Variable-resistance material memories include a metal spacer spaced apart and next to the diode. Processes include the formation of one of the buried salicide word line and the metal spacer. Devices include the variable-resistance material memories and one of the buried salicided word line and the spacer word line.
1. A process of forming a memory structure, comprising:
forming a first recess in a semiconductive substrate by use of a hard mask to define a pillar formed at least in part of a material of the semiconductive substrate;
depositing a metal material within the first recess, and establishing conditions to form a silicide within the material of the semiconductive substrate surrounding the first recess;
patterning the silicide to define a word line extending through the pillar;
forming a second recess in the hard mask, the second recess exposing an upper surface of the pillar;
forming a diode in the second recess; and
forming a variable-resistance material coupled to the diode.
2. The process of claim 1 , wherein the metal material is heated to form the word line extending through the pillar.
3. The process of claim 1 , wherein forming the diode in the second recess in the hard mask comprises:
etching the hard mask to form the second recess in the hard mask;
forming an epitaxial first film on the upper surface of the pillar; and
forming an epitaxial second film on the epitaxial first film.
4. The process of claim 3 , wherein forming the variable-resistance material comprises siliciding a portion of the epitaxial second film to form a silicide contact.
5. The process of claim 4 , wherein forming the variable-resistance material further comprises forming a bottom electrode on the silicide contact.
6. The process of claim 5 , wherein forming the variable-resistance material further comprises forming the variable-resistance material on the bottom electrode.
7. The process of claim 6 , wherein forming the variable-resistance erial further comprises forming a top electrode on the variable-resistance material.
8. The process of claim 7 , further comprising forming a bit line above the variable-resistance material and coupled to the variable-resistance material via the top electrode.
9. The process of claim 1 , wherein the word line includes cobalt silicide.
10. The process of claim 1 , wherein the variable-resistance material is selected from an alloy, a quasi-metal composition, a metal oxide, and a chalcogenide.
11. The process of claim 1 wherein the variable-resistance material includes a phase-change material.
12. The process of claim 1 , wherein the variable-resistance material includes one or more of a gallium-containing material, a germanium-containing material, an indium-containing material, an antimony-containing material, a tellurium-containing material, a selenium-containing material, an arsenic-containing material, an aluminum-containing material, a tin-containing material, a palladium-containing material, a silver-containing material, or a colossal magneto-resistive film.
13. The process of claim 1 , wherein the variable-resistance material includes a doped chalcogenide glass of the general formula A x B y , B selected from sulfur, selenium, and tellurium, and mixtures thereof, and A includes at least one element from Group III-A, Group IV-A, Group V-A, or Group VII-A of the periodic table.