Sensor with droplet retaining structure
This disclosure describes methods and devices that assist in forming biosensors. Specifically, features that align solutions containing molecules to be immobilized on biosensors. A retaining structure may be disposed at least partially around a target surface of a substrate. A resonating structure may be disposed on the target surface. A droplet of functionalized material may be disposed on the resonating structure and the target surface, which may be auto-aligned and retained by the retaining structure on the target surface to consistently cover the resonating structure.
1. A sensor with a droplet retaining structure comprising:
a substrate defining a target surface and a retaining structure extending at least partially around the target surface,
wherein the retaining structure comprises a channel having a height extending in a direction orthogonal to the target surface and into the substrate, and a width extending in a direction parallel to the target surface; and
a resonating structure disposed on the target surface of the substrate,
wherein a portion of the target surface between the resonating structure and the retaining structure has a width that allows for full coverage of the resonating structure with a droplet of functionalized material such that the droplet of functionalized material auto-aligns with the resonating structure and is prevented from moving.
2. The sensor of claim 1 , wherein the height of the retaining structure is at least 0.01 micrometers.
3. The sensor of claim 1 , wherein the portion of the target surface between the resonating structure and the retaining structure has a width equal to at least 5 micrometers.
4. The sensor of claim 1 , wherein the portion of the target surface between the resonating structure and the retaining structure has a width equal to at most 25 micrometers.
5. The sensor of claim 1 , further comprising an insulating layer disposed on the resonating structure and configured to couple to the functionalized material in the droplet.
6. The sensor of claim 5 , wherein the insulating layer comprises silane.
7. The sensor of claim 5 , further comprising an oxide layer disposed between the resonating structure and the insulating layer.
8. The sensor of claim 1 , wherein the retaining structure extends entirely around the target surface.
9. The sensor of claim 1 , wherein the channel of the retaining structure comprises sidewalls, wherein the sidewalls are 60-degree sidewalls.
10. The sensor of claim 1 , wherein the resonating structure comprises a piezoelectric layer.
11. A sensor with a droplet retaining structure comprising:
a substrate defining a target surface and a retaining structure extending at least partially around the target surface, the retaining structure having a height extending in a direction orthogonal to the target surface and a width extending in a direction parallel to the target surface; and
a resonating structure disposed on the target surface of the substrate,
wherein a portion of the target surface between the resonating structure and the retaining structure has a width that allows for full coverage of the resonating structure with a droplet of functionalized material such that a volume of the droplet of functionalized material required to cover the resonating structure is minimized, the droplet auto-aligns with the resonating structure and the droplet is prevented from moving outside of the target surface.
12. The sensor of claim 11 , wherein the retaining structure extends entirely around the target surface.
13. The sensor of claim 11 , wherein the height of the retaining structure is at least 0.01 micrometers.
14. The sensor of claim 11 , wherein the portion of the target surface between the resonating structure and the retaining structure has a width equal to at least 5 micrometers.
15. The sensor of claim 11 , wherein the portion of the target surface between the resonating structure and the retaining structure has a width equal to at most 25 micrometers.
16. The sensor of claim 11 , wherein the retaining structure comprises a wall having a height extending out of the substrate.
17. The sensor of claim 16 , wherein the wall comprises a hydrophobic material.
18. The sensor of claim 11 , wherein the retaining structure comprises a sidewall surface extending from the target surface, wherein the sidewall surface forms an angle with the target surface with an absolute value of at least 60 degrees.
19. The sensor of claim 18 , wherein the sidewall surface forms an angle with the target surface with an absolute value equal to 90 degrees.
20. The sensor of claim 11 , wherein the resonating structure comprises a piezoelectric layer.