Methods of forming memory arrays
View Patent ↗Some embodiments include methods of forming memory arrays. A stack of semiconductor material plates may be patterned to subdivide the plates into pieces. Electrically conductive tiers may be formed along sidewall edges of the pieces. The pieces may then be patterned into an array of wires, with the array having vertical columns and horizontal rows. Individual wires may have first ends joining to the electrically conductive tiers, may have second ends in opposing relation to the first ends, and may have intermediate regions between the first and second ends. Gate material may be formed along the intermediate regions. Memory cell structures may be formed at the second ends of the wires. A plurality of vertically-extending electrical interconnects may be connected to the wires through the memory cell structures, with individual vertically-extending electrical interconnects being along individual columns of the array. Some embodiments include memory arrays incorporated into integrated circuitry.
1. A method of forming a memory array, comprising:
forming a stack comprising vertically-spaced semiconductor material plates;
etching through the plates to subdivide the plates into planar pieces;
forming horizontally-extending electrically conductive tiers along and in electrical connection with sidewall edges of the planar pieces;
patterning the planar pieces into an array of wires; the array comprising vertical columns and horizontal rows; the electrically conductive tiers interconnecting wires of individual rows of the array; individual wires having first ends joining to the electrically conductive tiers, having second ends in opposing relation to the first ends, and having intermediate regions between the first and second ends;
forming at least one gate material along the intermediate regions of the wires;
forming memory cell structures at the second ends of the wires; and
forming a plurality of vertically-extending electrical interconnects connected to the wires through the memory cell structures; individual vertically-extending electrical interconnects being along individual columns of the array.
2. The method of claim 1 wherein insulative material sheets are provided between the plates; and wherein the insulative material of the sheets is patterned during the subdividing of the plates into the planar pieces, as well as during the patterning of the planar pieces into the array of wires.
3. The method of claim 1 wherein the forming of the stack comprises:
forming alternating layers of first and second semiconductor materials, where the first semiconductor material is selectively removable relative to the second semiconductor material; and
selectively removing the first semiconductor material relative to the second semiconductor material.
4. The method of claim 3 wherein the one of the first and second semiconductor materials consists of silicon, and wherein the other of the first and second semiconductor materials consists of silicon/germanium.
5. The method of claim 3 wherein the one of the first and second semiconductor materials is n-type doped, and wherein the other of the first and second semiconductor materials is p-type doped.
6. The method of claim 5 wherein layers of electrically insulative material are provided between the alternating layers of first and second semiconductor materials.
7. The method of claim 6 wherein the layers of electrically insulative material consist of silicon dioxide.
8. The method of claim 1 wherein the forming of the electrically conductive tiers comprises:
doping the semiconductor material of the sidewall edges of the planar pieces; and
forming metal silicide runners from the doped semiconductor material.
9. The method of claim 1 wherein the forming of the electrically conductive tiers comprises:
recessing the semiconductor material of the sidewall edges of the planar pieces; and
forming electrically conductive lines within the recesses.
10. The method of claim 8 wherein the metal silicide runners comprise one or more of cobalt silicide, nickel silicide and titanium silicide.