SENSOR USING FERROELECTRIC FIELD-EFFECT TRANSISTOR

• US 20110309415A1
• Filed: 06/18/2010
• Published: 12/22/2011
• Est. Priority Date: 06/18/2010
• Status: Abandoned Application

• Current Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Ng, Tse Nga, Sambandan, Sanjiv, Kist, Rene Jan Peter
• Application Number:
  US12/818,999
• Publication Number:
  US 20110309415A1
• Time in Patent Office: Days
• US Class Current: 257/254
• CPC Class Codes: G01L 1/005 by electrical means and not provided for in G01L1/06 - G01L1/22
• CPC Class Codes: G01L 1/16 using properties of piezoelectric devices
• CPC Class Codes: H01L 29/40111 the electrodes comprising a layer which is used for its ferroelectric properties
• CPC Class Codes: H01L 29/516 with at least one ferroelectric layer
• CPC Class Codes: H01L 29/6684 with a ferroelectric gate insulator
• CPC Class Codes: H01L 29/78391 the gate comprising a layer which is used for its ferroelectric properties
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure
• CPC Class Codes: H10N 30/857 Macromolecular compositions

Abstract

An embodiment is a method and apparatus to sense strain or pressure. A ferroelectric field effect transistor (feFET) structure has a semiconductor layer and a ferroelectric dielectric layer. The feFET structure is capable of sensing strain or pressure.

One disclosed feature of the embodiments is a method to fabricate a strain or pressure sensor. A circuit is printed to form a ferroelectric field effect transistor (feFET) structure having a ferroelectric dielectric layer and a semiconductor layer. The feFET structure is capable of sensing strain or pressure.

Claims

1. An apparatus comprising:

a semiconductor layer; and

a ferroelectric dielectric layer formed together with the semiconductor layer into a ferroelectric field effect transistor (feFET) structure capable of sensing strain or pressure.

2. The apparatus of claim 1 further comprising:

a flexible substrate attached to the feFET structure.

3. The apparatus of claim 2 wherein the flexible substrate is one of a flexible wire, a strip, and an area patch.

4. The apparatus of claim 1 wherein the ferroelectric dielectric layer comprises a polymer or an inorganic ferroelectric composite or a composite of organic and inorganic materials.

5. The apparatus of claim 1 wherein the semiconductor layer is an organic semiconductor or an inorganic thin film.

6. The apparatus of claim 1 wherein the feFET structure has a bottom-gate structure or a top-gate structure.

7. The apparatus of claim 6 wherein the bottom-gate structure comprises:

a gate electrode;

the ferroelectric dielectric layer deposited on the gate electrode;

source and drain electrodes deposited on the ferroelectric dielectric layer; and

the semiconductor layer deposited between the source and drain electrodes and on the ferroelectric dielectric layer.

8. The apparatus of claim 6 wherein the top-gate structure comprises:

source and drain electrodes;

the semiconductor layer deposited between the source and drain electrodes;

the ferroelectric dielectric layer deposited on the source and drain electrodes and the semiconductor layer; and

a gate electrode deposited on the ferroelectric dielectric layer.

9. The apparatus of claim 7 wherein source-drain current decreases under tension when radius of curvature of the flexible substrate is reduced.

10. The apparatus of claim 8 wherein source-to-drain current decreases under tension when radius of curvature of the flexible substrate is reduced.

11. The apparatus of claim 1 wherein the feFET structure comprises an array of transistors, each of the transistors having a ferroelectric dielectric layer and a semiconductor layer.

12. A method comprising:

printing a circuit to form a ferroelectric field effect transistor (feFET) structure having a ferroelectric dielectric layer and a semiconductor layer, the feFET structure capable of sensing strain or pressure.

13. The method of claim 12 further comprising:

attaching feFET structure to a flexible substrate.

14. The method of claim 12 wherein the ferroelectric dielectric layer comprises a polymer or an inorganic ferroelectric composite or a composite of organic and inorganic materials.

15. The method of claim 12 wherein the semiconductor layer comprises an organic semiconductor or an inorganic thin film.

16. The method of claim 12 wherein printing the circuit comprises:

printing a gate electrode;

depositing the ferroelectric dielectric layer on the gate electrode;

printing source and drain electrodes on the ferroelectric dielectric layer; and

printing the semiconductor layer between the source and drain electrodes and on the ferroelectric dielectric layer.

17. The method of claim 12 wherein printing the circuit comprises:

printing source and drain electrodes;

printing the semiconductor layer deposited between the source and drain electrodes;

depositing the ferroelectric dielectric layer on the source and drain electrodes and the semiconductor layer; and

printing a gate electrode on the ferroelectric dielectric layer.

18. A system comprising:

a structure having a curved surface; and

a sensor attached the curved surface to sense pressure applied to the structure, the sensor comprising an array of transistors, each of the transistors having;

a semiconductor layer, and

a ferroelectric dielectric layer formed together with the semiconductor layer into a ferroelectric field effect transistor (feFET) structure attached to the flexible substrate to sense the pressure.

19. The system of claim 18 wherein the sensor further comprising:

a flexible substrate attached to the array of transistors.

20. The system of claim 19 wherein each of the transistors has a bottom-gate structure or a top-gate structure.