Saw devices, processes for making them, and methods of use

• US 8,143,681 B2
• Filed: 04/20/2007
• Issued: 03/27/2012
• Est. Priority Date: 04/20/2006
• Status: Active Grant

• Current Assignee: George Washington University
• Original Assignee: George Washington University
• Inventors: ZAGHLOUL, MONA, Tigli, Onur, Nordin, Anis Nurashikin
• Primary Examiner(s): Wilson, Allan R
• Application Number:
  US11/738,460
• Publication Number:
  US 20080230859A1
• Time in Patent Office: 1,803 Days
• Field of Search: 257/416, 257/E45.006, 310313 B-313 D
• US Class Current: 257/416
• CPC Class Codes: G01N 2021/1729 Piezomodulation
• 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 2291/0423 Surface waves, e.g. Rayleigh waves, Love 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 29/2462 Probes with waveguides, e.g. SAW devices
• CPC Class Codes: G01N 29/326 compensating for temperature variations
• CPC Class Codes: H03H 3/08 for the manufacture of resonators or networks using surface acoustic waves
• CPC Class Codes: H03H 9/42 using surface acoustic waves devices for manipulating acoustic surface waves in general G10K11/36
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

The design, fabrication, post-processing and characterization of a novel SAW (Surface Acoustic Wave) based bio/chemical sensor in CMOS technology is introduced. The sensors are designed in AMI 1.5 μm 2 metal, 2 poly process. A unique maskless post processing sequence is designed and completed. The three post-processing steps are fully compatible with any CMOS technology. This allows any signal control/processing circuitry to be easily integrated on the same chip. ZnO is used as the piezoelectric material for the SAW generation. A thorough characterization and patterning optimization of the sputtered ZnO was carried out. The major novelties that are introduced in the SAW delay line features are: The embedded heater elements for temperature control, compensation and acoustic absorbers that are designed to eliminate edge reflections and minimize triple transit interference. Both of these attributes are designed by using the CMOS layers without disturbing the SAW performance.

Claims

1. An integrated circuit device comprising:

a complementary metal oxide semiconductor (CMOS) device including a silicon substrate, and at least a first metal layer and a second metal layer overlaying the first metal layer;

an absorber formed from stacking the first metal layer, the second metal layer and polysilicon; and

a surface acoustic wave device comprising;

at least two interdigital transducers arranged in one of the first metal layer and the second metal layer; and

a piezoelectric material deposited over top of the at least two interdigital transducers, such that the interdigital transducers are embedded in the piezoelectric material.

2. The integrated circuit of claim 1, wherein the at least two interdigital transducers form a delay line.

3. The integrated circuit of claim 1, wherein the piezoelectric material is zinc oxide.

4. The integrated circuit of claim 1, further including an n-well in the silicon substrate, the n-well being operative as a heater.

5. An integrated circuit device comprising:

a complementary metal oxide semiconductor (CMOS) device including a silicon substrate having an n-well operative as a heater, and at least a first metal layer and a second metal layer overlaying the first metal layer; and

a surface acoustic wave device forming a delay line comprising;

at least two interdigital transducers arranged in the first metal layer;

an absorber formed from stacking the first metal layer, the second metal layer and polysilicon; and

a ZnO piezoelectric material deposited over top of the at least two interdigital transducers and the absorber, such that the interdigital transducers and the absorber are embedded in the piezoelectric material.

6. An integrated circuit device comprising:

a complementary metal oxide semiconductor (CMOS) device including a silicon substrate having at least a first metal layer and a second metal layer; and

a surface acoustic wave device forming a resonator comprising;

a shield formed in the first metal layer;

at least two interdigital transducers arranged in the second metal layer;

a reflector formed in a third metal layer; and

a ZnO piezoelectric material deposited over top of the shield, the at least two interdigital transducers and the reflector, such that the shield, the interdigital transducers and the reflector are embedded in the piezoelectric material.

7. The integrated circuit of claim 6, further including an n-well in the silicon substrate, the n-well being operative as a heater.

8. An integrated circuit device comprising:

a complementary metal oxide semiconductor (CMOS) device including a silicon substrate, and at least a first metal layer and a second metal layer overlaying the first metal layer; and

a first surface acoustic wave device forming a resonator comprising;

a shield in the first metal layer;

at least two interdigital transducers arranged in the second metal layer; and

a second acoustic wave device forming a delay line comprising;

at least two interdigital transducers arranged in the first metal layer; and

an absorber formed from stacking the first metal layer, the second metal layer and polysilicon;

wherein a piezoelectric material is deposited over top of the first and the second acoustic wave devices, such that the first acoustic wave device and the second acoustic wave device are embedded in the piezoelectric material.

9. The integrated circuit of claim 8, wherein the piezoelectric material is zinc oxide.

10. The integrated circuit of claim 8, further including an n-well in the silicon substrate, the n-well being operative as a heater.

11. An integrated circuit device comprising:

a complementary metal oxide semiconductor (CMOS) device including a silicon substrate, and at least a first metal layer and a second metal layer overlaying the first metal layer; and

a surface acoustic wave device comprising;

a metal shield layer formed in the first metal layer;

at least two interdigital transducers arranged in the second metal layer, the at least two interdigital transducers forming a resonator;

a reflector in a third metal layer; and

a piezoelectric material deposited over top of the at least two interdigital transducers, such that the interdigital transducers are embedded in the piezoelectric material.

12. The integrated circuit of claim 11, wherein the piezoelectric material is zinc oxide.

13. The integrated circuit of claim 11, further including an n-well in the silicon substrate, the n-well being operative as a heater.