Infrared imaging using arrays of SiO2 micromechanical detectors

Area of Science:

• Materials Science
• Optoelectronics
• Sensor Technology

Background:

• Infrared (IR) imaging requires sensitive detectors.
• Existing IR detectors often need vacuum packaging and complex fabrication.
• Bimaterial detectors offer a potential alternative for IR sensing.

Purpose of the Study:

• To fabricate an array of bimaterial detectors for IR imaging.
• To utilize silicon dioxide (SiO2) as a structural material.
• To simplify the microfabrication process for IR detectors.

Main Methods:

• Fabrication of bimaterial detectors with an optical resonant cavity.
• Removal of substrate material beneath the active detector area.
• Simplified microfabrication using four photolithographic steps without wet etching.

Main Results:

• Achieved thermomechanical deflection sensitivity of 7.9×10(-3) rad/K.
• Demonstrated operation at room temperature and atmospheric pressure.
• Measured average noise equivalent temperature difference (NETD) of ~200 mK, with some elements reaching 50 mK.

Conclusions:

• The developed bimaterial detectors are suitable for IR imaging without vacuum packaging.
• The simplified fabrication process reduces complexity and cost.
• The detectors show promising performance for practical IR imaging applications.