Plasmonic transducer having two metal elements with a gap disposed therebetween

1. A method comprising:

forming, on a substrate, a waveguide having an elongated delivery axis that extends to a media-facing surface;

forming at least two metal elements with a first gap therebetween over the waveguide, wherein the first gap is elongated along the delivery axis, and wherein the at least two metal elements are joined at a narrowed tip proximate the media-facing surface; and

forming a small gap through the narrowed tip, the small gap extending from the first gap to the media-facing surface.

2. The method of claim 1 , wherein forming the small gap comprises:

depositing a layer of photoresist on the narrowed tip;

forming a trench through the photoresist layer; and

cutting the small gap through the trench via an angled mill.

3. The method of claim 1 , wherein forming the small gap comprises:

depositing a first hard mask layer on part of the narrowed tip so that an edge of the first hard mask layer is along the small gap;

depositing a conformal coating over at least the edge of the first hard mask layer, the conformal coating having a thickness conforming to a dimension of the small gap;

depositing a second hard mask layer over the conformal coating;

planing the second hard mask layer to expose the conformal coating over the edge of the first hard mask layer between the first and second hard masks; and

etching the exposed conformal coating between the first and second hard mask to form the small gap.

4. The method of claim 1 , wherein the at least two metal elements comprises gold.

5. The method of claim 1 , wherein the at least two metal elements form a near-field transducer.

6. The method of claim 1 , wherein the waveguide comprises a three-dimensional, channel waveguide, and wherein the first gap is over a core of the waveguide.

7. A method comprising:

forming a thin stop layer over a metallic seed layer disposed on a substrate;

depositing a thick layer of dielectric material over the thin stop layer;

milling a trench having an angled wall in the thick layer;

removing a portion of the thin stop layer within the trench to expose the metallic seed layer; and

forming at least two metal elements with a gap therebetween in the trench, wherein the gap is elongated along a delivery axis of a waveguide that extends to a media facing surface, wherein the at least two metal elements are angled to form a narrowed end proximate a media-facing surface, and wherein the narrowed end is further narrowed by the angled wall of the trench.

8. The method of claim 7 , wherein forming the at least two metal elements comprises:

applying a photoresist layer in the trench, wherein the photoresist layer comprises voids in the shape of the at least two metal elements;

filling in the voids to form the at least two metal elements; and

removing the photoresist material.

9. The method of claim 7 , further comprising:

filling the gap with a second dielectric material;

planing the metal elements and second dielectric material; and

overlaying a thin layer of metallic material over the metal elements to form a narrowed tip at the narrowed end, wherein the narrowed tip comprises a small gap extending from the media-facing surface to the gap of the at least two metal elements.

10. The method of claim 7 , wherein the metallic seed layer and the at least two metal elements comprise gold.

11. The method of claim 7 , wherein the at least two metal elements form a near-field transducer.

12. The method of claim 7 , wherein the thin stop layer comprises amorphous carbon.

13. A method comprising:

forming, on a substrate, a waveguide having an elongated delivery axis that extends to a media-facing surface;

forming at least one metal element over the waveguide, the at least one metal element being elongated along the delivery axis;

depositing a hard stop layer over an end of the at least one metal element;

forming a thick metal layer over the at least one metal element and the hard stop layer;

forming a sloped wall through the thick metal layer stopping at the hard stop layer.

14. The method of claim 13 , wherein forming the sloped wall comprises using a reactive ion beam etch.

15. The method of claim 13 , further comprising forming a narrowed tip extending from the end of the at least one metal element.

16. The method of claim 13 , wherein forming the at least one metal element comprises forming two metal elements with a gap therebetween, and wherein the hard stop layer and the thick metal layer are formed over the two metal elements.

17. The method of claim 13 , wherein the at least one metal elements comprises gold.

18. The method of claim 13 , wherein the hard stop layer comprises amorphous carbon.

19. The method of claim 13 , wherein the waveguide comprises a three-dimensional, channel waveguide.