Three-dimensional microelectronic devices including horizontal and vertical patterns
A vertical NAND flash memory device includes a substrate having a face and a string of serially connected flash memory cells on the substrate. A first flash memory cell is adjacent the face, and a last flash memory cell is remote from the face. The flash memory cells include repeating layer patterns that are stacked on the face, and a pillar that extends through the series of repeating layer patterns. The pillar includes at least one oblique wall. At least two of the series of repeating layer patterns in the string are of different thicknesses. Other vertical microelectronic devices and related fabrication methods are also described.
1. A vertical NAND flash memory device comprising:
a cell string electrically connected between a first selection transistor and a second selection transistor, the cell string comprising memory cell transistors connected in series,
wherein the cell string comprises a first structure including first conductive patterns vertically stacked on a substrate, a second structure including second conductive patterns vertically stacked on the first structure, and a pillar penetrating the first structure and the second structure, and
wherein each of the first conductive patterns has a first thickness and each of the second conductive patterns has a second thickness greater than the first thickness.
2. The vertical NAND flash memory device of claim 1 , wherein the cell string further comprises a third structure including third conductive patterns vertically stacked on the second structure, and wherein each of the third conductive patterns has a third thickness greater than the second thickness.
3. The vertical NAND flash memory device of claim 1 , wherein each of the first and second selection transistors comprises a conductive pattern and the pillar extends therethrough.
4. The vertical NAND flash memory device of claim 1 , wherein the pillar includes a first portion adjacent to the first structure and a second portion adjacent to the second structure, and a width of the pillar is narrower in the first portion than in the second portion.
5. The vertical NAND flash memory device of claim 1 , wherein the pillar includes at least one oblique wall.
6. The vertical NAND flash memory device of claim 5 wherein the pillar has a regular polygonal cross-sectional shape.
7. The vertical NAND flash memory device of claim 1 , wherein a first overlapping area between the pillar and one of the first conductive patterns is substantially the same as a second overlap area between the pillar and one of the second conductive patterns.
8. The vertical NAND flash memory device of claim 1 , further comprising a data storage layer disposed between the first and the second structures and the pillar.
9. The vertical NAND flash memory device of claim 1 , wherein the pillar comprises a conductive material.
10. The vertical NAND flash memory device of claim 1 , wherein the pillar comprises a semiconductor material.
11. A vertical NAND flash memory device comprising:
a cell string electrically connected between a first selection transistor and a second selection transistor, the cell string comprising memory cell transistors connected in series,
wherein the cell string comprises a plurality of conductive patterns stacked on a substrate and a pillar extending through the plurality of conductive patterns, and
wherein the memory cell transistors comprise a plurality of groups of memory cell transistors, wherein at least two of conductive patterns in a given group have a first thickness and at least two of conductive patterns in different groups have a second thickness different from the first thickness.
12. The vertical NAND flash memory device of claim 11 , wherein each of the first and second selection transistors comprises a conductive pattern and the pillar extends therethrough.
13. The vertical NAND flash memory device of claim 11 , wherein the pillar is wider remote from an upper surface of the substrate compared to adjacent the upper surface.
14. The vertical NAND flash memory device of claim 11 , wherein the pillar comprises a conductive material.
15. The vertical NAND flash memory device of claim 11 , wherein the pillar comprises a semiconductor material.
16. The vertical NAND flash memory device of claim 11 wherein the pillar has a regular polygonal cross-sectional shape.