SEMICONDUCTOR DEVICE-BASED SENSORS AND METHODS ASSOCIATED WITH THE SAME

• US 20080185616A1
• Filed: 01/31/2008
• Published: 08/07/2008
• Est. Priority Date: 06/28/2004
• Status: Abandoned Application

• Current Assignee: Nitronex Corporation
• Original Assignee: Nitronex Corporation
• Inventors: Piner, Edwin L., Linthicum, Kevin J., Johnson, Jerry W.
• Application Number:
  US12/023,500
• Publication Number:
  US 20080185616A1
• Time in Patent Office: Days
• US Class Current: 257/253
• CPC Class Codes: G01N 27/129 Diode type sensors, e.g. gas sensitive Schottky diodes capacitor type sensors G01N27/227; field-effect transistor type sensors G01N27/414
• CPC Class Codes: G01N 27/4148 Integrated circuits therefor, e.g. fabricated by CMOS processing CMOS processing per se H01L21/82
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

Semiconductor device-based chemical sensors and methods associated with the same are provided. The sensors include regions that can interact with chemical species being detected. The chemical species may, for example, be a component of a fluid (e.g., gas or liquid). The interaction between the chemical species and a region of the sensor causes a change in a measurable property (e.g., an electrical property) of the device. These changes may be related to the concentration of the chemical species in the medium being characterized.

Claims

1. A FET-based chemical sensor designed to detect a chemical species comprising:

a semiconductor material region;

a source electrode formed on the semiconductor material region;

a drain electrode formed on the semiconductor material region;

a gate electrode formed on the semiconductor material region; and

a sensing region, separated from the gate electrode, and capable of interacting with the chemical species to change a measurable property of the chemical sensor.

2. The sensor of claim 1, wherein the sensing region comprises a sensing layer.

3. The sensor of claim 2, wherein the sensing layer has a thickness of less than 500 nm.

4. The sensor of claim 2, wherein the sensing region further comprises a surface region of the semiconductor material region positioned under the sensing layer.

5. The sensor of claim 1, wherein the sensing region comprises an exposed surface region of the semiconductor material region.

6. The sensor of claim 1, wherein the sensing region is formed between the source electrode and the drain electrode.

7. The sensor of claim 1, wherein a ratio of sensing electrode surface area to total channel surface area is greater than 0.35.

8. The sensor of claim 1, wherein the sensing region comprises a sensing electrode.

9. The sensor of claim 8, wherein a separate voltage may be applied to each of the source, drain, gate and sensing electrodes.

10. The sensor of claim 1, wherein respective electrical contacts to each of the source, drain, gate and sensing electrodes are formed on a backside of the sensor.

11. The sensor of claim 1, wherein the sensor is substantially free of electrical contacts on a frontside of the sensor in areas separate from the sensing region.

12. The sensor of claim 1, wherein the semiconductor region comprises a gallium nitride material layer.

13. The sensor of claim 12, wherein the sensing region is formed, at least in part, in the gallium nitride material layer.

14. The sensor of claim 12, wherein the gallium nitride material layer has a crack level of less than about 0.005 micron/micron².

15. The sensor of claim 1, further comprising a substrate.

16. The sensor of claim 15, wherein the substrate is a silicon substrate.

17-28. -28. (canceled)

29. A semiconductor device-based chemical sensor comprising:

a semiconductor material region;

a first electrode formed on the semiconductor material region;

a second electrode formed on the semiconductor material region;

a first electrical contact extending from a backside of the sensor to the first electrode;

a second electrical contact extending from a backside of the sensor to the second electrode; and

a sensing region, separated from the first electrode and the second electrode, and capable of interacting with the chemical species to change a measurable property of the chemical sensor.

30. The chemical sensor of claim 29, further comprising a third electrode, wherein the first electrode is a source electrode, the second electrode is a drain electrode and the third electrode is a gate electrode.

31. A method of detecting chemical species comprising:

exposing a FET-based chemical sensor to a medium comprising chemical species; and

measuring changes in drain current of the sensor resulting from adsorption of the chemical species on a sensing region separated from the gate electrode to detect chemical species.

32-39. -39. (canceled)