Vertically stacked field programmable nonvolatile memory and method of fabrication
AssigneeSanDisk 3D LLC
InventorsVivek Subramanian, James Cleeves
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Abstract
A very high density field programmable memory is disclosed. An array is formed vertically above a substrate using several layers, each layer of which includes vertically fabricated memory cells. The cell in an N level array may be formed with N+1 masking steps plus masking steps needed for contacts. Maximum use of self alignment techniques minimizes photolithographic limitations. In one embodiment the peripheral circuits are formed in a silicon substrate and an N level array is fabricated above the substrate.
Claims3
A process for fabricating a 3-D semiconductor memory device comprising the steps of:
- forming a first stack comprising a P-N diode and a state change element;
- forming a second stack comprising a P-N diode and a state change element overlying the first stack,
- wherein the first and second stacks comprise elements of a pillar in a 3-D memory array, wherein the 3-D memory array comprises a plurality of layers of memory cells stacked vertically above one another, and
- forming edge regions on the pillar using a plasma oxidation process.
A process for fabricating a pillar in a 3-D semiconductor memory device, wherein the pillar includes a P-N diode and a state change element vertically arranged between orthogonally disposed conductors leads, the process comprising the steps of:
- forming a semiconductor layer;
- and
- oxidizing at least a portion of the semiconductor layer in a plasma to form an oxide antifuse layer overlying the semiconductor layer;
- wherein the 3-D semiconductor memory device comprises a plurality of layers of memory cells stacked vertically above one another.
Dependencies are inferred from the claim text.