Self-Aligned Split Gate Flash Memory
First Claim
1. A split gate memory cell, comprising:
- a select gate disposed over a semiconductor substrate, separated therefrom by a gate dielectric layer;
a memory gate arranged at one side of the select gate;
a charge trapping layer having a vertical portion disposed between neighboring sidewalls of the select gate and the memory gate and a lateral portion extending under the memory gate;
source/drain regions disposed in the semiconductor substrate at opposite sides of the select gate and the memory gate;
a memory gate spacer arranged directly above the memory gate having a lateral dimension smaller than that of the memory gate, wherein the memory gate spacer has an inner sidewall disposed along an upper portion of the charge trapping layer and an outer sidewall recessed back laterally relative to an outer sidewall of the memory gate;
a dielectric liner continuously lining the outer sidewall of the memory gate, extending on a portion of a top surface of the memory gate not covered by the memory gate spacer, and extending upwardly along the outer sidewall of the memory gate spacer; and
a sidewall spacer disposed alongside the dielectric liner;
wherein the dielectric liner extends underneath the sidewall spacer and separates the sidewall spacer from the semiconductor substrate.
1 Assignment
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Accused Products
Abstract
The present disclosure relates to a self-aligned split gate memory cell, and an associated method. The self-aligned split gate memory cell has a memory gate with a flat top surface. A memory gate spacer is arranged directly above the memory gate having a lateral dimension smaller than that of the memory gate. The memory gate spacer has an inner sidewall disposed along an upper portion of a charge trapping layer and an outer sidewall recessed back laterally relative to an outer sidewall of the memory gate. In some embodiments, a dielectric liner is continuously lined the outer sidewall of the memory gate, extending on a portion of the top surface of the memory gate not covered by the memory gate spacer, and extending upwardly along the outer sidewall of the memory gate spacer.
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Citations
23 Claims
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1. A split gate memory cell, comprising:
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a select gate disposed over a semiconductor substrate, separated therefrom by a gate dielectric layer; a memory gate arranged at one side of the select gate; a charge trapping layer having a vertical portion disposed between neighboring sidewalls of the select gate and the memory gate and a lateral portion extending under the memory gate; source/drain regions disposed in the semiconductor substrate at opposite sides of the select gate and the memory gate; a memory gate spacer arranged directly above the memory gate having a lateral dimension smaller than that of the memory gate, wherein the memory gate spacer has an inner sidewall disposed along an upper portion of the charge trapping layer and an outer sidewall recessed back laterally relative to an outer sidewall of the memory gate; a dielectric liner continuously lining the outer sidewall of the memory gate, extending on a portion of a top surface of the memory gate not covered by the memory gate spacer, and extending upwardly along the outer sidewall of the memory gate spacer; and a sidewall spacer disposed alongside the dielectric liner; wherein the dielectric liner extends underneath the sidewall spacer and separates the sidewall spacer from the semiconductor substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A pair of split gate memory cells disposed over a semiconductor substrate, comprising:
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a common source/drain region shared by the pair of memory cells disposed in the semiconductor substrate; a pair of select gates corresponding to the pair of memory cells respectively arranged on opposite sides of the common source/drain region, each of the select gates having a planar upper surface; a pair of memory gates corresponding to the pair of memory cells arranged about opposite sides of the pair of select gates respectively, each of the memory gates being a cuboid shape and having planar upper surface and sidewalls; a charge trapping layer separating each of the memory gates from the corresponding select gates and extending under each of the memory gates; a pair of memory gate spacers disposed directly above each of the memory gates, wherein inner sidewalls of the memory gate spacers are vertically aligned with inner sidewalls of the corresponding memory gates and outer sidewalls of the memory gate spacers are recessed back from outer sidewalls of the corresponding memory gates; a pair of dielectric liners disposed along outer sidewalls of the pair of the memory gates and select gates, extending on a portion of upper surfaces of the memory gates not covered by the memory gate spacers, and extending upwardly to cover outer sidewalls of the memory gate spacers; and a pair of sidewall spacers disposed on the pair of dielectric liners and covering outer sidewalls of the pair of dielectric liners; wherein the pair of sidewall spacers respectively have outermost sidewalls vertically aligned with outermost sidewalls of the pair of dielectric liners. - View Dependent Claims (12, 13, 14, 15)
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16-20. -20. (canceled)
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21. A split gate memory cell, comprising:
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source/drain regions disposed within a semiconductor substrate; a select gate with a cuboid shape disposed between the source/drain regions and over the semiconductor substrate, the select gate separated from the semiconductor substrate by a gate dielectric layer; a memory gate with a cuboid shape arranged at one side of the select gate; a charge trapping layer comprising a charge trapping component sandwiched between a lower oxide layer and an upper oxide layer, the charge trapping layer disposed between the select gate and the memory gate and extending under the memory gate; a memory gate spacer arranged on the memory gate having an inner sidewall disposed along an upper portion of the charge trapping layer and an outer sidewall recessed back laterally relative to an outer sidewall of the memory gate; and a dielectric liner comprising a lower vertical portion and an upper vertical portion connected by a lateral portion, wherein the lower vertical portion lines the outer sidewall of the memory gate, the lateral portion extends along a portion of a top surface of the memory gate not covered by the memory gate spacer, and the upper vertical portion extends upwardly along the outer sidewall of the memory gate spacer. - View Dependent Claims (22, 23)
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Specification