Semiconductor device-based sensors

• US 7,361,946 B2
• Filed: 06/28/2004
• Issued: 04/22/2008
• Est. Priority Date: 06/28/2004
• Status: Expired due to Fees

• Current Assignee: MACOM Technology Solutions Holdings, Inc.
• Original Assignee: Nitronex Corporation
• Inventors: Piner, Edwin L., Linthicum, Kevin J., Johnson, Jerry W.
• Primary Examiner(s): Pert; Evan
• Assistant Examiner(s): TRAN, TAN N
• Application Number:
  US10/879,704
• Publication Number:
  US 20050285155A1
• Time in Patent Office: 1,394 Days
• Field of Search: 257/253, 257/258, 257/414, 435/180
• 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 comprising a gallium nitride material layer;

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 comprising the gallium nitride material layer and a sensing electrode, laterally 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 surface region of the gallium nitride material layer positioned under the sensing electrode.

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

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

5. The sensor of claim 1, wherein a separate voltage may be applied to each of the source, drain, gate and sensing electrodes.

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

7. The sensor of claim 6, wherein the substrate is a silicon substrate.

8. The sensor of claim 6, further comprising a compositionally-graded transition layer formed between the substrate and the semiconductor material region.

9. The sensor of claim 1, wherein the chemical species is a gaseous species.

10. The sensor of claim 1, wherein the interaction between the chemical species and the sensing region results in a change in the drain current of the sensor.

11. The sensor of claim 1, wherein the interaction between the chemical species and the sensing region changes the surface potential of the gallium nitride material layer.

12. The sensor of claim 1, wherein the chemical species is adsorbed by the sensing region during operation.

13. The sensor of claim 1, wherein the sensing region is positioned between the gate electrode and the drain electrode.

14. The sensor of claim 1, wherein the source, gate and drain electrodes are formed on the gallium nitride material layer.

15. The sensor of claim 1, wherein the gate electrode is isolated from the chemical species.