Circular surface acoustic wave (SAW) devices, processes for making them, and methods of use

• US 8,018,010 B2
• Filed: 07/02/2008
• Issued: 09/13/2011
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: George Washington University
• Original Assignee: George Washington University
• Inventors: Tigli, Onur, Zaghloul, Mona
• Primary Examiner(s): Wilson; Allan R
• Application Number:
  US12/166,646
• Publication Number:
  US 20090114798A1
• Time in Patent Office: 1,168 Days
• Field of Search: 257/416, 257/E45.006, 250/200, 310/313.R, 331/167
• US Class Current: 257/416
• 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: H03B 5/326 the resonator being an acoustic wave device, e.g. SAW or BAW device
• CPC Class Codes: H03H 9/02881 of diffraction of wave beam
• CPC Class Codes: H03H 9/14547 Fan shaped; Tilted; Shifted; Slanted; Tapered; Arched; Stepped finger transducers
• CPC Class Codes: H03H 9/14561 Arched, curved or ring shaped transducers

Abstract

The design, fabrication, post-processing and characterization of a novel circular design 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 chip having a circular design SAW device as an on-chip component, the SAW device comprising one or more interdigital transducers formed in a substantially closed concentric circle arrangement.

2. The chip of claim 1, wherein the chip is a microprocessor.

3. The chip of claim 1, wherein the chip is a programmable integrated circuit.

4. The chip of claim 1, wherein the chip is a microelectromechanical system (MEMS).

5. The chip of claim 1, wherein the chip is a nanoelectromechanical system (NEMS).

6. The chip of claim 1, wherein the circular design SAW device is a CMOS device.

7. The chip of claim 6, wherein the circular design SAW device includes an absorber structure formed from stacked CMOS layers.

8. The chip of claim 7, wherein the CMOS layers are metal1, metal2, polysilicon and inter-layer oxides.

9. The chip of claim 1, wherein the concentric circular interdigital transducer structures are aligned on a common focal point.

10. The chip of claim 9, wherein the interdigital transducer structures are interconnected using CMOS layers.

11. The chip of claim 10, wherein the substantially closed concentric circle arrangement is a continuous completely closed concentric circle arrangement.

12. The chip of claim 1, wherein the substantially closed concentric circle arrangement is a continuous completely closed concentric circle arrangement.

13. A circular design SAW device having an absorber structure, the absorber structure formed from stacked CMOS layers of metal1, metal2, polysilicon and inter-layer oxides, wherein the SAW device comprises one or more interdigital transducers formed in a substantially closed concentric circle arrangement.

14. An LC circuit which comprises a circular design SAW device and an amplifier on the same chip, the SAW device comprising one or more interdigital transducers formed in a substantially closed concentric circle arrangement.

15. A local oscillator, which comprises the LC circuit of claim 14 connected to a Pierce oscillator.