Split gate non-volatile memory cells with three-dimensional FinFET structure
A memory device including a plurality of upwardly extending fins in a semiconductor substrate upper surface. A memory cell is formed on a first of the fins, and includes spaced apart source and drain regions in the first fin, with a channel region extending along top and opposing side surfaces of the first fin between the source and drain regions. A floating gate extends along a first portion of the channel region. A select gate extends along a second portion of the channel region. A control gate extends along the floating gate. An erase gate extends along the source region. A second of the fins has a length that extends in a first direction which is perpendicular to a second direction in which a length of the first fin extends. The source region is formed in the first fin at an intersection of the first and second fins.
1. A memory device, comprising:
a semiconductor substrate having an upper surface with a plurality of upwardly extending fins, wherein each of the fins including first and second side surfaces that oppose each other and that terminate in a top surface;
a memory cell formed on a first fin of the plurality of fins, comprising:
spaced apart source and drain regions in the first fin, with a channel region of the first fin extending along the top surface and the opposing side surfaces of the first fin between the source and drain regions,
a floating gate that extends along a first portion of the channel region, wherein the floating gate extends along and is insulated from the first and second side surfaces and the top surface of the first fin,
a select gate that extends along a second portion of the channel region, wherein the select gate extends along and is insulated from the first and second side surfaces and the top surface of the first fin,
a control gate that extends along and is insulated from the floating gate, and
an erase gate that extends along and is insulated from the source region;
a second fin of the plurality of fins has a length that extends in a first direction, wherein the first fin has a length that extends in a second direction that is perpendicular to the first direction, and wherein the source region is formed in the first fin at an intersection of the first and second fins.
2. The memory device of claim 1 , wherein the erase gate extends along and is insulated from the first and second side surfaces and the top surface of the first fin, and extends along and is insulated from the first and second side surfaces and the top surface of the second fin.
3. The memory device of claim 2 , wherein the erase gate extends along and is insulated from an upper edge of the floating gate, and wherein the erase gate includes a notch facing the upper edge of the floating gate.
4. The memory device of claim 1 , further comprising:
a logic device formed on a third fin of the plurality of fins, comprising:
spaced apart logic source and logic drain regions in the third fin, with a logic channel region of the third fin extending along the top surface and the opposing side surfaces of the third fin between the logic source and logic drain regions, and
a logic gate that extends along the logic channel region, wherein the logic gate extends along and is insulated from the first and second side surfaces and the top surface of the third fin.
5. The memory device of claim 4 , wherein the third fin extends higher than the first and second fins relative to the substrate.
6. The memory device of claim 4 , further comprising:
a second logic device formed on a fourth fin of the plurality of fins, comprising:
spaced apart second logic source and logic drain regions in the fourth fin, with a second logic channel region of the fourth fin extending along the top surface and the opposing side surfaces of the fourth fin between the second logic source and drain regions, and
a second logic gate that extends along the second logic channel region, wherein the second logic gate extends along and is insulated from the first and second side surfaces and the top surface of the fourth fin.
7. The memory device of claim 6 , wherein:
the logic gate is insulated from the third fin by first insulation material;
the second logic gate is insulated from the fourth fin by second insulation material;
the first insulation material has a thickness that is greater than that of the second insulation material.
8. A memory device, comprising:
a semiconductor substrate having an upper surface with a plurality of upwardly extending first fins and a plurality of upwardly extending second fins, wherein:
each of the first and second fins including first and second side surfaces that oppose each other and that terminate in a top surface,
each of the first fins has a length that extends in a first direction,
each of the second fins has a length that extends in a second direction that is perpendicular to the first direction, and
the first fins intersect the second fins in a grid like manner;
a plurality of memory cells each of which is formed on one of the first fins and comprises:
spaced apart source and drain regions in the one first fin, with a channel region of the one first fin extending along the top surface and the opposing side surfaces of the one first fin between the source and drain regions,
a floating gate that extends along a first portion of the channel region, wherein the floating gate extends along and is insulated from the first and second side surfaces and the top surface of the one first fin,
a select gate that extends along a second portion of the channel region, wherein the select gate extends along and is insulated from the first and second side surfaces and the top surface of the one first fin,
a control gate that extends along and is insulated from the floating gate, and
an erase gate that extends along and is insulated from the source region,
wherein the source region is formed at an intersection of the one first fin and one of the second fins.
9. The memory device of claim 8 , wherein the memory cells are arranged in rows extending in the second direction and columns extending in the first direction, and wherein each of the second fins electrically connects together the source regions of a row of the memory cells.
10. The memory device of claim 8 , wherein for each of the memory cells, the erase gate extends along and is insulated from the first and second side surfaces and the top surface of the one first fin, and extends along and is insulated from the first and second side surfaces and the top surface of the one second fin.
11. The memory device of claim 10 , wherein for each of the memory cells, the erase gate extends along and is insulated from an upper edge of the floating gate and includes a notch facing the upper edge of the floating gate.
12. The memory device of claim 8 , further comprising:
the semiconductor substrate upper surface further includes a plurality of upwardly extending third fins;
a plurality of logic devices each of which is formed on one of the third fins and comprises:
spaced apart logic source and logic drain regions in the one third fin, with a logic channel region of the one third fin extending along the top surface and the opposing side surfaces of the one third fin between the logic source and logic drain regions, and
a logic gate that extends along the logic channel region, wherein the logic gate extends along and is insulated from the first and second side surfaces and the top surface of the one third fin.
13. The memory device of claim 12 , wherein each of the plurality of third fins extends higher than each of the plurality of first fins and each of the plurality of second fins relative to the substrate.
14. The memory device of claim 12 , wherein one of the logic gates is insulated from one of the third fins by first insulation material, another one of the logic gates is insulated from another one of the third fins by a second insulation material, and the first insulation material has a thickness that is greater than that of the second insulation material.