Patent ID: 7745265

Claim:
A method of making a monolithic, three dimensional NAND string, comprising: forming a first memory cell over a second memory cell; forming a first word line for the first memory cell; forming a second word line for the second memory cell; forming a bit line; and forming a source line; wherein: the first word line extends from the first memory cell in a first direction; the second word line extends from the second memory cell in a second direction not parallel to the first direction; the NAND string is formed vertically over a substrate; a select transistor is located on the substrate or in a trench in the substrate; the first memory cell is located in a first device level; the second memory cell is located in a second device level located on the select transistor and below the first device level; a semiconductor active region of the first memory cell is formed epitaxially on a semiconductor active region of the second memory cell; the semiconductor active region of the second memory cell is formed epitaxially on a semiconductor active region of the select transistor; a first charge storage dielectric is located between the semiconductor active region of the first memory cell and the first word line; a second charge storage dielectric is located between the semiconductor active region of the second memory cell and the second word line; the semiconductor active region of the first memory cell comprises a first pillar; the semiconductor active region of the second memory cell comprises a second pillar; the semiconductor active region of the select transistor comprises a third pillar; the first pillar and the second pillar each comprise an upper second conductivity type semiconductor region above a first conductivity type semiconductor region above a lower second conductivity type region; the lower second conductivity type semiconductor region in the first pillar contacts the upper second conductivity type semiconductor region in the second pillar; the first pillar is not aligned with the second pillar, such that the first pillar extends laterally past the second pillar; the second pillar is not aligned with the third pillar, such that the second pillar extends laterally past the third pillar; the first, second, and third pillars are disposed about a first, second, and third central axis, respectively, each of which extend in a vertical direction substantially normal to the substrate; the first central axis is laterally offset from the second central axis; and the second central axis is laterally offset from the third central axis.