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US 8,999,828 B2Granted
Method and device for a split-gate flash memory with an extended word gate below a channel region
AssigneeGlobalfoundries Singapore Pte. Ltd.
InventorsEng Huat Toh, Shyue Seng (Jason) Tan
Life of this patent
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Abstract
A split gate memory cell is fabricated with a word gate extending below an upper surface of a substrate having the channel region. An embodiment includes providing a band engineered channel with the word gate extending there through. Another embodiment includes forming a buried channel with the word gate extending below the buried channel.
Claims13
A method comprising:
- providing a memory gate stack over a channel region;
- providing a word gate extending from an upper portion at an upper surface of the memory gate stack to a lower portion below an upper surface of a substrate at the channel region and below an upper surface of the substrate at source and drain regions, wherein the lower portion of the word gate contacts both the channel region and a source or drain region, and wherein the upper portion of the word gate and the lower portion of the word gate have the same width;
- and
- planarizing the memory gate stack and the word gate such that an upper surface of the memory gate stack and an upper surface of the word gate are substantially coplanar.
1 more element
A method comprising:
- providing a memory gate stack over a channel region;
- removing a portion of the memory gate stack to form an opening;
- providing a word gate, having sidewall spacers on side surfaces thereof and extending from an upper portion at an upper surface of the memory gate stack to a lower portion below an upper surface of a substrate at the channel region and below an upper surface of the substrate at source and drain regions, in the opening, wherein the lower portion of the word gate contacts both the channel region and a source or drain region, and wherein the upper portion of the word gate and the lower portion of the word gate have the same width;
- and
- planarizing the memory gate stack and the word gate such that an upper surface of the memory gate stack and an upper surface of the word gate are substantially coplanar.
2 more elements
Dependencies are inferred from the claim text.