Resistive memory devices using a carbon-based conductor line and methods for forming the same

A method of forming a resistive memory device, comprising:

• forming an array of rail structures that extend along a first horizontal direction over a substrate, wherein each of the rail structures comprises at least one bit line;
• forming a layer stack of a resistive memory material layer and a selector material layer over the array of rail structures;
• and
• forming word lines that laterally extend along a second horizontal direction and are laterally spaced apart along the first horizontal direction over the layer stack, wherein each of the word lines includes a respective horizontally-extending portion that overlie the rail structures and a respective row of downward-protruding portions that protrude downward from the respective horizontally-extending portion,
• wherein:
• the word lines or at least a subset of the bit lines comprise a carbon-based conductive material containing hybridized carbon atoms in a hexagonal arrangement;
• each rail structure within the array of rail structures comprises a vertical stack including a respective lower bit line, a respective inter-bit-line dielectric rail, and a respective upper bit line;
• wherein one of the respective lower bit line and the respective upper bit line comprises the carbon-based conductive material;
• and
• wherein another of the respective lower bit line and the respective upper bit line comprises a conductive material other than the carbon-based conductive material.

A method of forming a memory device, comprising:

• forming vertical stacks of a respective lower bit line, a respective inter-bit-line dielectric rail, and a respective upper bit line;
• forming a layer stack of a resistive memory material layer and a selector material layer over sidewall of the vertical stacks;
• and
• forming word lines that laterally extend along a horizontal direction that is perpendicular to a lengthwise direction of the vertical stacks, wherein each of the word lines includes a respective horizontally-extending portion that overlie each of the vertical stacks and a respective row of downward-protruding portions that protrude downward from the respective horizontally-extending portion between neighboring pairs of the vertical stacks,
• wherein:
• at least one set selected from a set of the word lines, a set of the lower bit lines, and a set of the upper bit lines comprises a carbon-based conductive material containing hybridized carbon atoms in a hexagonal arrangement;
• the lower bit lines comprise a first material selected from the carbon-based conductive material and a conductive material other than the carbon-based conductive material;
• and
• the upper bit lines comprise a second material that is different from the first material and selected from the carbon-based conductive material and the conductive material other than the carbon-based conductive material.