Three-dimensional memory
First Claim
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1. A process for fabricating two memory levels in a memory array comprising:
- forming a first conductive layer;
depositing a first semiconductor layer over the first conductive layer, the first semiconductive layer being doped with a first conductivity type dopant;
forming a first antifuse layer over the first semiconductor layer;
depositing a second semiconductor layer doped with a second conductivity type dopant over the first antifuse layer;
in a first etch step, etching the first conductive layer, the first semiconductor layer, the first antifuse layer, and the second semiconductor layer into a plurality of first parallel, spaced-apart rail-stacks;
filling the space between the first rail-stacks with a first insulator;
planarizing the first upper surface of the first rail-stacks and the first insulator;
forming a second conductive layer over the second semiconductor layer;
depositing a third semiconductor layer doped with a second conductivity type dopant over the second conductive layer;
in a second etch step, etching the second conductive layer and the third semiconductor layer into a plurality of second parallel, spaced-apart rail-stacks;
filling the space between the second rail-stacks with a second insulator;
planarizing the second upper surface of the second insulator and the second rail-stacks;
forming a second antifuse layer on the planarized second upper surface;
depositing a fourth semiconductor layer doped with a first conductivity type dopant over the second antifuse layer;
forming a third conductive layer;
in a third etch step, etching the third semiconductor layer and third conductive layer to form third parallel, spaced-apart rail-stacks;
filling the space between the third rail-stacks with a third insulator.
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Abstract
A 3D semiconductor memory is described having rail-stacks which define conductive lines and cells. The memory levels are organized in pairs with each pair showing common lines in adjacent levels.
7 Citations
10 Claims
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1. A process for fabricating two memory levels in a memory array comprising:
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forming a first conductive layer;
depositing a first semiconductor layer over the first conductive layer, the first semiconductive layer being doped with a first conductivity type dopant;
forming a first antifuse layer over the first semiconductor layer;
depositing a second semiconductor layer doped with a second conductivity type dopant over the first antifuse layer;
in a first etch step, etching the first conductive layer, the first semiconductor layer, the first antifuse layer, and the second semiconductor layer into a plurality of first parallel, spaced-apart rail-stacks;
filling the space between the first rail-stacks with a first insulator;
planarizing the first upper surface of the first rail-stacks and the first insulator;
forming a second conductive layer over the second semiconductor layer;
depositing a third semiconductor layer doped with a second conductivity type dopant over the second conductive layer;
in a second etch step, etching the second conductive layer and the third semiconductor layer into a plurality of second parallel, spaced-apart rail-stacks;
filling the space between the second rail-stacks with a second insulator;
planarizing the second upper surface of the second insulator and the second rail-stacks;
forming a second antifuse layer on the planarized second upper surface;
depositing a fourth semiconductor layer doped with a first conductivity type dopant over the second antifuse layer;
forming a third conductive layer;
in a third etch step, etching the third semiconductor layer and third conductive layer to form third parallel, spaced-apart rail-stacks;
filling the space between the third rail-stacks with a third insulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A process for fabricating two memory levels in a memory array comprising:
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forming a first conductive layer;
depositing a first semiconductor layer over the first conductive layer, the first semiconductor layer being doped with a first conductivity type dopant;
forming a first antifuse layer over the first semiconductor layer;
depositing a second semiconductor layer doped with a second conductivity type dopant over the first antifuse layer;
etching the first conductive layer, the first semiconductor layer, the first antifuse layer, and the second semiconductor layer into a plurality of first parallel, spaced-apart rail-stacks;
filling the space between the first rail-stacks with a first insulator;
planarizing the first upper surface of the first rail-stacks and the first insulator;
forming a second conductive layer over the second semiconductor layer;
depositing a third semiconductor layer doped with a second conductivity type dopant over the second conductive layer;
depositing a fourth semiconductor layer doped with a first conductivity type dopant over the third semiconductor layer;
etching the second semiconductor layer, second conductive layer, third semiconductor layer and fourth semiconductor layer into a plurality of second parallel, spaced-apart rail-stacks and an etched fourth semiconductor layer;
filling the space between the second rail-stacks and the etched fourth semiconductor layer with a second insulator;
planarizing the second upper surface of the second insulator and the etched fourth semiconductor layer;
forming a second antifuse layer on be planarized second upper surface;
forming a third conductive layer;
etching the third conductive layer and etched fourth semiconductor layer to form third parallel, spaced-apart rail-stacks;
filling the space between the third rail-stacks with a third insulator. - View Dependent Claims (10)
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Specification