Nonvolatile memory device with layout to minimize void formation and method of making the same
AssigneeFreescale Semiconductor, Inc.
InventorAnirban Roy
Life of this patent
Estimating the term…
Abstract
A memory device can include an array of NOR memory cells, each memory cell including a floating gate, a source on a source side of the floating gate, a drain on a drain side of the floating gate, a drain contact on the drain, and a source contact on the source. The source contacts are connected to a common source line. A plurality of bit lines are connected to respective drains in a column of the memory cells. A plurality of word lines, each word line coupled to respective floating gates in a row of the memory cells. Spacing between the word lines on the drain side is greater than spacing between the word lines on the source side.
Claims20
A memory device, comprising:
- an array of NOR memory cells, each NOR memory cell including a floating gate, a source on a source side of the floating gate, a drain on a drain side of the floating gate, a drain contact on the drain, and a discrete source contact on the source, wherein the source contact is connected to a common source line;
- bit lines, each bit line connecting each of the drains in a column of the NOR memory cells;
- and
- word lines, each word line coupled to each of the floating gates in a row of the NOR memory cells, wherein spacing between one of the word lines on the drain side is greater than spacing between one of the word lines on the source side.
A memory device comprising:
- a first NOR memory cell having a first source, a first drain, a first floating gate, a separate conductive contact on the first source, and a conductive contact on the first drain;
- a second NOR memory cell arranged in a column with the first NOR memory cell and having the first source and the separate conductive contact on the first source in common with the first NOR memory cell, a second drain, a second floating gate, a conductive contact on the second drain;
- and
- a third NOR memory cell arranged in a column with the first and second NOR memory cells and having a second source, the second drain in common with the second NOR memory cell, a third floating gate, and a separate conductive contact on the second source;
- a fourth NOR memory cell arranged in a row with the first NOR memory cell and having a third source, a separate conductive contact on the third source, a third drain, a fourth floating gate, and a conductive contact on the third drain;
- wherein a first spacing between the first and second floating gates is less than a second spacing between the second and third floating gates.
A method of making a memory device comprising:
- forming a first NOR memory cell having a first source, a first drain, a first floating gate, a discrete conductive contact on the first source, and a conductive contact on the first drain;
- forming a second NOR memory cell arranged in a column with the first NOR memory cell and having the first source and the discrete conductive contact on the first source in common with the first NOR memory cell, a second drain, a second floating gate, a conductive contact on the second drain;
- forming a third NOR memory cell arranged in a column with the first and second NOR memory cells and having a second source, the second drain in common with the second NOR memory cell, a third floating gate, and a discrete conductive contact on the second source;
- forming a fourth NOR memory cell arranged in a row with the first NOR memory cell and having a third source, a discrete conductive contact on the third source, a third drain, a fourth floating gate, and a conductive contact on the third drain;
- forming a first word line coupled to the floating gate of the first NOR memory cell;
- forming a second word line coupled to the floating gate of the second NOR memory cell;
- and
- forming a third word line coupled to the floating gate of the third NOR memory cell,
- wherein a first spacing between the first and second word lines is less than a second spacing between the second and third word lines.
Dependencies are inferred from the claim text.