Buried low-resistance metal word lines for cross-point variable-resistance material memories

1. A process of forming a memory structure, comprising:

forming a first recess in an upper semiconductive substrate by use of a hard mask, wherein the upper semiconductive substrate is disposed above a lower semiconductive substrate;

forming a temporary spacer in the first recess;

forming a second recess that penetrates into the lower semiconductive substrate, and that forms a pillar in the upper semiconductive substrate;

forming a buried oxide in the lower semiconductive substrate and in the pillar;

removing the temporary spacer;

forming a nitride first spacer on the pillar;

forming a metal second spacer on the nitride first spacer;

forming a shallow trench isolation adjacent the pillar;

forming a diode in a recess of the hard mask that exposes the pillar at an upper surface thereof: and

forming a variable-resistance material coupled to the diode.

2. The process of claim 1 , wherein forming the diode in the recess of the hard mask that exposes the pillar at the upper surface thereof includes:

etching the hard mask to form the recess in the hard mask;

forming an epitaxial first film above and on the pillar at the uppersurface; and

forming a second film above and on the epitaxial first film.

3. The process of claim 2 , wherein forming the variable-resistance material that is coupled to the diode includes:

siliciding a portion of the second film to form a suicide contact;

forming a bottom electrode on the silicide contact;

forming the variable-resistance material on the bottom electrode; and

forming a top electrode on the variable-resistance material.

4. 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.

5. The process of claim 1 , wherein the variable-resistance material includes a phase-change material.

6. The process of claim I, 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.

7. The process of claim I, 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 VI -A of the periodic table.

8. The process of claim 3 , wherein the silicide contact includes cobalt silicide.

9. The process of claim 1 , wherein a silicide contact is formed in direct contact with the diode.