Thin-film transistor based piezoelectric strain sensor and method

• US 8,519,449 B2
• Filed: 07/23/2010
• Issued: 08/27/2013
• Est. Priority Date: 08/25/2009
• Status: Active Grant

• Current Assignee: Honeywell Romania Srl (Honeywell International Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Dumitru, Viorel-Georgel, Cobianu, Cornel, Costea, Stefan-Dan, Serban, Bogdan-Catalin
• Primary Examiner(s): Vu, David
• Assistant Examiner(s): FOX, BRANDON C
• Application Number:
  US12/842,298
• Publication Number:
  US 20110049579A1
• Time in Patent Office: 1,131 Days
• Field of Search: 257/254, 257/295
• US Class Current: 257/254
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• 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 29/0665 the shape of the body defining a nanostructure nanotechnology per se B82B
• CPC Class Codes: H01L 29/78654 Monocrystalline silicon transistors
• CPC Class Codes: H01L 29/78681 having a semiconductor body comprising AIIIBV or AIIBVI or AIVBVI semiconductor materials, or Se or Te
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure
• CPC Class Codes: H10K 10/468 characterised by the gate dielectrics
• CPC Class Codes: H10K 10/481 characterised by the gate conductors
• CPC Class Codes: H10K 85/221 Carbon nanotubes

Abstract

A piezoelectric strain sensor and method thereof for detecting strain, vibration, and/or pressure. The sensor incorporates a sequence of piezoelectric and semiconductor layers in a thin-film transistor structure. The thin-film transistor structure can be configured on a flexible substrate via a low-cost fabrication technique. The piezoelectric layer generates an electric charge resulting in a modulation of a transistor current, which is a measure of external strain. The sensor can be formed as a single gate field-effect piezoelectric sensor and a dual gate field-effect piezoelectric sensor. The semiconductor layer can be configured from a nanowire array resulting in a metal-piezoelectric-nanowire field effect transistor. The single and dual gate field-effect piezoelectric sensor offer increased sensitivity and device control due to the presence of the piezoelectric layer in the transistor structure and low cost manufacturability on large area flexible substrates.

Claims

1. A strain sensor, comprising:

a flexible substrate;

a thin-film transistor structure comprising at least one piezoelectric material layer formed below a semiconductor layer and deposited on said flexible substrate, wherein said at least one piezoelectric material layer generates an electric charge resulting in a modulation of a transistor current;

a metal gate layer located on said flexible substrate with respect to a source region and a drain region, wherein said at least one piezoelectric material layer of said thin-film transistor structure provides for an increased sensitivity and enhanced device control with respect to said strain sensor; and

wherein said thin-film transistor structure comprises a dual gate field effect sensor having said semiconductor layer sandwiched above said at least one piezoelectric material layer and below a second piezoelectric layer included in a structure of said dual gate field effect sensor wherein at least one channel region of said semiconductor layer is modulated by strain in said at least one piezoelectric material layer and said second piezoelectric layer.

2. The sensor of claim 1 wherein said semiconductor layer comprises a semiconductor carbon nanotube array.

3. The sensor of claim 2 wherein said semiconductor carbon nanotube array comprises a material selected from a group of materials comprising at least one of the following types of materials:

GaAs;

GaN;

SnO2;

In2O3;

ZnO;

InN;

AlInN; and

an array of carbon nanotubes.

4. The sensor of claim 2 wherein said carbon nanotube array is deposited on said semiconductor layer utilizing a printing technology.

5. The sensor of claim 2 wherein said at least one piezoelectric material layer and said semiconductor layer are configured on said flexible substrate utilizing a thin-film deposition technology.

6. The sensor of claim 1 wherein said flexible substrate comprises a material selected from a group of materials comprising at least one of the following types of materials:

a metallic foil.

7. The sensor of claim 1 wherein said at least one piezoelectric material layer comprises a material selected from a group of materials comprising at least one of the following types of materials:

lead zirconate titanate (PZT) film; and

aluminum nitride (AIN) film.

8. The sensor of claim 1 wherein said semiconductor layer comprises a thin film layer that includes a material selected from a group of materials comprising at least one of the following types of materials:

GaAs;

GaN;

SnO2;

In2O3;

ZnO;

InN; and

AlInN.

9. The sensor from claim 8 wherein said semiconductor layer is deposited via a printing technology utilizing nanoparticle-based inks.

10. The sensor from claim 8, wherein a liquid phase of said semiconductor layer comprising SnO2 or In2O3 is prepared utilizing a sol-gel technology and deposited by a printing technology.

11. The sensor of claim 1 wherein said at least one piezoelectric material layer and said semiconductor layer are configured on said flexible substrate utilizing a thin-film deposition technology.

12. The sensor of claim 11 wherein said thin-film deposition technology comprises a sputtering deposition.

13. The sensor of claim 1 further comprising a plurality of metal contacts deposited on said flexible substrate utilizing a printing technology.

14. A strain sensor, comprising:

a rigid substrate;

a nanowire/nanotube transistor structure comprising at least one piezoelectric material layer formed below a semiconductor carbon nanotube array and deposited on said substrate, wherein said piezoelectric layer generates an electric charge resulting in a modulation of a transistor current;

a metal gate layer located between a source region and a drain region, wherein said piezoelectric layer in said carbon nanotube transistor structure provides for an increased sensitivity and enhanced device control with respect to said strain sensor; and

wherein said nanowire/nanotube transistor structure comprises a dual gate field effect sensor having said semiconductor layer sandwiched above said at least one piezoelectric material layer and below a second piezoelectric layer included in said dual gate field effect sensor wherein at least one channel region of said semiconductor layer is modulated by strain in said at least one piezoelectric material layer and said second piezoelectric layer.