Ammonia gas sensor and its manufacturing method

• US 20040244466A1
• Filed: 06/06/2003
• Published: 12/09/2004
• Est. Priority Date: 06/06/2003
• Status: Abandoned Application

• Current Assignee: Chi-Yen Shen
• Original Assignee: Chi-Yen Shen
• Inventors: Shen, Chi-Yen
• Application Number:
  US10/455,319
• Publication Number:
  US 20040244466A1
• Time in Patent Office: Days
• US Class Current: 73/24.01
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0212 Binary gases
• CPC Class Codes: G01N 2291/0255 (Bio)chemical reactions, e.g. on biosensors
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0426 Bulk waves, e.g. quartz crystal microbalance, torsional waves
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/34 Generating the ultrasonic, sonic or infrasonic waves , e.g. electronic circuits specially adapted therefor

Abstract

The invention provides ammonia gas sensor and its manufacturing method. Said ammonia gas sensor comprises a piezoelectric substrate, a surface acoustic wave sensor, and a L-glutamic acid hydrochloride coating; said surface acoustic wave sensor and said L-glutamic acid hydrochloride coating are on the said piezoelectric substrate.

Claims

1. An ammonia gas sensor, comprises:

a piezoelectric substrate;

a surface acoustic wave device, and;

a L-glutamic acid hydrochloride coating, wherein said surface acoustic wave device and said L-glutamic acid hydrochloride coating are formed on said piezoelectric substrate.

2. The ammonia gas sensor described as in claim 1, wherein said piezoelectric substrate is a single-layer piezoelectric substrate.

3. The ammonia gas sensor described as in claim 1, wherein said piezoelectric substrate is a multilayer piezoelectric substrate.

4. The ammonia gas sensor described as in claim 2 or 3, wherein said piezoelectric substrate is made of quartz, lithium niobate (LiNbO3), lithium tantalante (LiTaO3), Li2B4O7 (LBO), barium titanate (BaTiO3), leadzirconate (PZT), zinc oxide, aluminum nitride, or combinations of those materials.

5. The ammonia gas sensor described as in claim 1, wherein Said surface acoustic wave device comprises a delay line, a one-port resonator, a two-port resonator, or a reflective delay line.

6. The ammonia gas sensor described as in claim 5, wherein said delay line is a dual delay line.

7. The ammonia gas sensor described as in claim 6, wherein said device comprises two IDTs.

8. The ammonia gas sensor described as in claim 5, wherein said IDTs are made of aluminum, gold, or another gold alloy.

9. The ammonia gas sensor described as in claim 7 further comprises an electronic oscillation circuit connected to said IDTs.

10. The ammonia gas sensor described as in claim 1, wherein said L-glutamic acid hydrochloride coating is formed on said piezoelectric substrate with L-glutamic acid hydrochloride solution.

11. The ammonia gas sensor described as in claim 10, wherein the deposition of said L-glutamic acid hydrochloride solution is done through spray coating or spin coating.

12. The ammonia gas sensor described in claim 9 further comprises a frequency counter connected to said electronic oscillation circuit to receive a signal generated by said electronic oscillation circuit.

13. A method for manufacturing ammonia gas sensors comprises the following procedures:

provide a substrate;

form a surface acoustic wave device on said substrate, and;

deposit a L-glutamic acid hydrochloride coating on said substrate.

14. The method of manufacturing ammonia gas sensors as described in claim 13, where said substrate is a single-layer substrate.

15. The method of manufacturing ammonia gas sensors as described in claim 13, where said substrate is a multilayer substrate.

16. The method of manufacturing ammonia gas sensors as described in claim 14 or 15, where said substrate is made of quartz, lithium niobate (LiNbO3), lithium tantalante (LiTaO3), Li2B4O7 (LBO), barium titanate (BaTiO3), leadzirconate (PZT), zinc oxide, aluminum nitride, or combinations of above materials.

17. The method of manufacturing ammonia gas sensors as described in claim 13, wherein the formation of said surface acoustic wave sensor is done with photolithography technology or lift-off technology.

18. The method of manufacturing ammonia gas sensors as described in claim 13, wherein said surface acoustic wave device comprises a delay line, a one-port resonator, a two-port resonator, or a reflective delay line.

19. The method of manufacturing ammonia gas sensors as described in claim 18, wherein said delay line is a dual delay line.

20. The method of manufacturing ammonia gas sensors as described in claim 19, wherein said system comprises two IDTs.

21. The method of manufacturing ammonia gas sensors as described in claim 20, wherein said IDTs are made of aluminum, gold, or another gold alloy.

22. The method of manufacturing ammonia gas sensors as described in claim 13, wherein The deposition of said L-glutamic acid hydrochloride coating is done with a L-glutamic acid hydrochloride solution through spray coating or spin coating.