Floating gate with unique profile by means of undercutting for split-gate flash memory device
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsShih-Chang Liu, Chi-Hsin Lo, Chia-Shiung Tsai, Chi-Wei Ho
Life of this patent
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Abstract
A split-gate flash memory device has a floating gate with a lateral recess at its bottom sidewall by adding an undercutting step. The split-gate flash memory device has a floating gate with a lateral recess on a substrate, an integrated dielectric layer lining the substrate, the sidewall and the lateral recess of the floating gate; a control gate on the integrated dielectric layer and covering at least part of the floating gate; and a dielectric spacer in the lateral recess between the integrated dielectric layer and the control gate.
Claims11
A split-gate flash memory device, comprising:
- a floating gate formed overlying a substrate, wherein a sidewall of said floating gate comprises a lateral recess;
- an integrated dielectric layer formed overlying said substrate, said sidewall and said lateral recess of said floating gate;
- a control gate formed overlying said integrated dielectric layer and covering at least part of said floating gate;
- and
- a dielectric spacer formed in said lateral recess between said integrated dielectric layer and said control gate;
- wherein said sidewall of said floating gate comprises a tapered sidewall making said floating gate become gradually narrower toward the top of said floating gate.
A split-gate flash memory device, comprising:
- a gate dielectric layer formed on a substrate;
- a floating gate formed on said gate dielectric layer, wherein said floating gate comprises a tapered sidewall and a lateral recess adjacent to the bottom of said tapered sidewall;
- a dielectric cap layer formed on the top surface of said floating gate;
- an integrated dielectric layer lining said substrate, said tapered sidewall and said lateral recess;
- a control gate formed on said integrated dielectric layer and covering at least part of said floating gate;
- and
- a dielectric spacer formed in said lateral recess between said integrated dielectric layer and said control gate;
- wherein said tapered sidewall makes said floating gate become gradually narrower toward the top end of said floating gate.
Dependencies are inferred from the claim text.