Fuse structure including monocrystalline semiconductor material layer and gap
View Patent ↗A fuse structure, a method for fabricating the fuse structure and a method for programming a fuse within the fuse structure each use a fuse material layer that is used as a fuse, and located upon a monocrystalline semiconductor material layer in turn located over a substrate. At least part of the monocrystalline semiconductor material layer is separated from the substrate by a gap. Use of the monocrystalline semiconductor material layer, as well as the gap, provides for enhanced uniformity and reproducibility when programming the fuse.
1. A method for fabricating a fuse structure comprising:
patterning a monocrystalline semiconductor material layer located upon a sacrificial layer located over a substrate to form in plan-view a wider end and narrower middle monocrystalline semiconductor material layer aligned upon a wider end and narrower middle sacrificial layer;
etching a narrow middle portion of the wider end and narrower middle sacrificial layer from beneath the wider end and narrower middle semiconductor material layer to provide a gap interposed between the narrow middle portion of the wider end and narrower middle monocrystalline semiconductor material layer and the substrate, wherein said etching further leaves a pedestal of the wider end and narrower middle sacrificial layer recessed under a wider end portion of the wider end and narrower middle semiconductor material layer and wherein said etching thus also extends the gap to include a location under a periphery of the wider end portion of the wider end and narrower middle semiconductor material layer; and
forming a fuse material layer upon one of:
the monocrystalline semiconductor material layer, and sequentially patterning the fuse material layer when patterning the monocrystalline semiconductor material layer; and
the wider end and narrower middle monocrystalline semiconductor material layer, said fuse material layer comprising a metal-semiconductor material.
2. A method for fabricating a fuse structure comprising:
patterning a monocrystalline semiconductor material layer located upon a sacrificial layer located over a substrate to form in plan-view a wider end and narrower middle monocrystalline semiconductor material layer aligned upon a wider end and narrower middle sacrificial layer;
etching at least a narrow middle portion of the wider end and narrower middle sacrificial layer to provide a gap between at least the narrow middle portion of the wider end and narrower middle monocrystalline semiconductor material layer and the substrate; and
forming a fuse material layer upon one of:
the monocrystalline semiconductor material layer, and sequentially patterning the fuse material layer when patterning the monocrystalline semiconductor material layer; and
the wider end and narrower middle monocrystalline semiconductor material layer.
3. The method of claim 2 wherein the fuse material layer comprises a metal-semiconductor material.
4. The method of claim 2 wherein the etching leaves a pedestal of the wider end and narrower middle sacrificial layer under a wider end portion of the wider end and narrower middle semiconductor material layer.
5. The method of claim 4 wherein the etching also leaves a gap under a wider end portion of the wider end and narrower middle semiconductor material layer.
6. The method of claim 4 wherein the etching does not leave a gap under a wider end portion of the wider end and narrower middle semiconductor material layer.
7. A method for fabricating a fuse structure comprising:
providing a substrate including a vertical stack of a surface semiconductor layer, a base dielectric layer, and a base semiconductor layer;
patterning said surface semiconductor layer into a shape including a narrower middle portion, a first end portion laterally abutting said narrower middle portion and having a greater width than said narrower middle portion, and a second end portion laterally abutting said narrower middle portion and not abutting said first end portion and having a greater width than said narrower middle portion; and
isotropically etching exposed portions of said base dielectric layer, wherein an entirety of a bottom surface of said narrower middle portion is exposed between said first end portion and said second end portion, and wherein a portion of said base dielectric layer abuts a portion of a bottom surface of said first end portion and another portion of said base dielectric layer abuts a portion of a bottom surface of said second portion after said isotropically etching.
8. The method of claim 7 further comprising depositing a backfilling dielectric layer on said patterned surface semiconductor layer, wherein a gap separating said entirety of said bottom surface of said narrower middle portion and said base dielectric layer is formed after said depositing of said backfilling dielectric layer.
9. The method of claim 8 further comprising:
planarizing said backfilling dielectric layer;
exposing a top surface of said patterned surface semiconductor layer; and
forming a metal semiconductor layer directly on said top surface of said patterned surface semiconductor layer.
10. The method of claim 7 wherein said surface semiconductor layer is a monocrystalline semiconductor material layer.
11. The method of claim 7 further comprising:
forming a pad dielectric on said surface semiconductor layer; and
forming a hard mask on said pad dielectric.