A CMOS Compatible Pyroelectric Mid-Infrared Detector Based on Aluminium Nitride

Area of Science:

• Materials Science
• Infrared Spectroscopy
• Semiconductor Devices

Background:

• Infrared radiation detection is crucial for applications like gas sensing.
• Existing detectors often face limitations in cost, size, or performance.
• Mid-infrared sensing, particularly for CO2 absorption, requires specialized detectors.

Purpose of the Study:

• To develop a cost-effective, CMOS-compatible pyroelectric detector for mid-infrared applications.
• To utilize aluminum nitride (AlN) as the pyroelectric material for enhanced performance.
• To investigate the impact of device dimensions on detector performance.

Main Methods:

• Fabrication of pyroelectric detectors using semiconductor mass fabrication processes.
• Integration of AlN as the pyroelectric layer on a Si3N4/SiO2 membrane for thermal decoupling.
• Testing of detectors at wavelengths relevant to CO2 absorption in the mid-infrared spectrum.
• Characterization of devices with varying detector and membrane sizes.

Main Results:

• Successful fabrication of CMOS-compatible pyroelectric detectors using AlN.
• Demonstration of detector functionality in the mid-infrared, near the CO2 absorption band.
• Measurement of a low noise equivalent power (NEP) of 5.3 × 10⁻⁹ W/√Hz in initial demonstrator devices.
• Analysis of the influence of device and membrane dimensions on performance.

Conclusions:

• The developed AlN-based pyroelectric detector is a promising solution for mid-infrared sensing.
• CMOS compatibility and semiconductor fabrication enable mass production and cost reduction.
• The achieved low NEP indicates high sensitivity for infrared absorption sensing applications.