IP Library › Granted Patent US 12,339,247
Granted Patent B2
US 12,339,247 · App. 17/715,282 · Granted Jun 24, 2025

Field effect transistor with buried fluid-based gate and method

Inventors: Mark D. Levy (Williston, VT); Siva P. Adusumilli (South Burlington, VT); Aaron L. Vallett (Jericho, VT)
Assignee: GlobalFoundries U.S. Inc.
G01N27/4148G01N27/4145
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Quick Facts
Patent No.
US 12,339,247
App. No.
17/715,282
Granted
Jun 24, 2025
Kind
B2
Abstract

Disclosed is a semiconductor structure including a device (e.g., a field effect transistor (FET), a biosensor FET (bioFET) or an ion-sensitive FET (ISFET)) with a fluid-based gate. The structure includes a substrate, an intermediate layer on the substrate, and a semiconductor layer on the intermediate layer. The device includes, within the semiconductor layer, a source region, a drain region, and a channel region between the source and drain regions. The structure includes, for the fluid-base gate, a cavity within the intermediate layer below the channel region and lined with a dielectric liner. Optionally, the exposed surface of the dielectric liner within the cavity is functionalized. Additional dielectric layers are stacked on the semiconductor layer and at least one port extends essentially vertically through the dielectric layers, the semiconductor layer and the dielectric liner to the cavity so as to allow fluid for the fluid-based gate to flow into the cavity.

Claims (48)

1. A structure comprising:

a substrate;

an intermediate layer on the substrate;

a semiconductor layer on the intermediate layer; and

a dielectric liner lining a cavity in the intermediate layer and further lining at least one opening that extends through the semiconductor layer to the cavity, wherein the dielectric liner is immediately adjacent to the semiconductor layer within the cavity and wherein at least one port extends through the semiconductor layer and the dielectric liner to the cavity.

2. The structure of claim 1 , wherein, within the at least one opening and the cavity, the dielectric liner has an exposed surface comprising receptors.

3. The structure of claim 1 , wherein the dielectric liner comprises any of silicon dioxide and a high-K dielectric material.

4. The structure of claim 1 , wherein the intermediate layer comprises any of an insulator layer and an additional semiconductor layer comprising a different semiconductor material than the semiconductor layer and the substrate.

5. The structure of claim 1 , further comprising:

an additional dielectric layer on the semiconductor layer; and

an interlayer dielectric material layer on the additional dielectric layer, wherein the at least one port extends through the interlayer dielectric material layer, the additional dielectric layer, the semiconductor layer and the dielectric liner to the cavity.

6. The structure of claim 5 , wherein the at least one opening extends through the additional dielectric layer and the semiconductor layer to the cavity, and wherein the interlayer dielectric material layer caps the at least one opening.

7. The structure of claim 1 , further comprising a buried well region in the substrate adjacent to the cavity.

8. The structure of claim 1 , further comprising isolation regions in the semiconductor layer positioned laterally adjacent to an active device region, wherein the active device region comprises a channel region positioned laterally between a source region and a drain region and wherein the cavity is aligned below the channel region.

9. The structure of claim 8 , further comprising additional isolation regions extending from the isolation regions through the intermediate layer and into the substrate.

10. The structure of claim 8 , wherein the semiconductor layer has a first surface adjacent to the intermediate layer and a second surface opposite the first surface and wherein the structure further comprises a gate structure adjacent to the channel region on the second surface of the semiconductor layer.

11. The structure of claim 8 , wherein the semiconductor layer has a first surface adjacent to the intermediate layer and a second surface opposite the first surface and wherein the structure further comprises at least one contact adjacent to the channel region on the second surface of the semiconductor layer.

12. A structure comprising:

a substrate;

an intermediate layer on the substrate;

a semiconductor layer on the intermediate layer; and

a device comprising:

a source region, a drain region, and a channel region, wherein the channel region is within the semiconductor layer and positioned laterally between the source region and the drain region; and

a dielectric liner lining a cavity in the intermediate layer and further lining at least one opening that extends through the semiconductor layer to the cavity,

wherein the cavity is aligned below the channel region,

wherein, within the at least one opening and the cavity, the dielectric liner is immediately adjacent to the semiconductor layer and has an exposed surface comprising bioreceptors, and

wherein at least one port extends through the semiconductor layer and the dielectric liner to the cavity.

13. A method comprising:

forming a cavity in an intermediate layer between a substrate and a semiconductor layer on the intermediate layer, wherein at least one opening extends through the semiconductor layer to the cavity;

lining the at least one opening and the cavity with a dielectric liner such that the dielectric liner is immediately adjacent to the semiconductor layer within the cavity; and

forming at least one port that extends through the semiconductor layer and the dielectric liner to the cavity.

14. The method of claim 13 , further comprising processing an exposed surface of the dielectric liner such that the exposed surface comprises receptors.

15. The method of claim 13 , wherein the intermediate layer comprises any of an insulator layer and an additional semiconductor layer comprising a different semiconductor material than the semiconductor layer and the substrate.

16. The method of claim 13 ,

wherein the lining of the at least one opening and the cavity comprises: performing atomic layer deposition of the dielectric liner, and

wherein the dielectric liner comprises any of silicon dioxide and a high-K dielectric material.

17. The method of claim 13 , wherein the forming of the cavity comprises:

forming the at least one opening extending through an additional dielectric layer in the semiconductor layer and further extending through the semiconductor layer to the intermediate layer; and

etching the intermediate layer to form the cavity.

18. The method of claim 17 , further comprising forming an interlayer dielectric material layer on the additional dielectric layer, wherein the interlayer dielectric material layer caps the at least one opening and wherein the at least one port is formed so as to extend through the interlayer dielectric material layer, the additional dielectric layer, the semiconductor layer and the dielectric liner to the cavity.

19. The method of claim 13 , further comprising:

forming isolation regions in the semiconductor layer positioned laterally adjacent to an active device region; and

forming, in the active device region, a channel region positioned laterally between a source region and a drain region, wherein the cavity is formed so as to be aligned below the channel region.

20. The method of claim 19 , wherein the semiconductor layer has a first surface adjacent to the intermediate layer and a second surface opposite the first surface and wherein the method further comprises any of:

forming additional isolation regions extending from the isolation regions through the intermediate layer and into the substrate;

forming a buried well region in the substrate;

forming a gate structure adjacent to the channel region on the second surface of the semiconductor layer; and

forming at least one contact adjacent to the channel region on the second surface of the semiconductor layer.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 7, 2022
From: LEVY, MARK D.; ADUSUMILLI, SIVA P.; VALLETT, AARON L.
To: GLOBALFOUNDRIES U.S. INC.
Reel/Frame 059530/0877 →
Continuity (1)
Related Publication 20230324332A1 · Oct 12, 2023
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