SiGe/Si Multi-Quantum-Well Micro-Bolometer Array Design and Fabrication with Heterogeneous Integration.

Area of Science:

• Materials Science
• Infrared Imaging Technology
• Semiconductor Device Fabrication

Background:

• Traditional micro-bolometer materials limit infrared imaging performance.
• Silicon-germanium/silicon multi-quantum-well (SiGe/Si MQWs) offer high TCR and low 1/f noise.
• Integrating high-performance SiGe/Si MQWs into micro-bolometers faces fabrication challenges.

Purpose of the Study:

• To develop a SiGe/Si MQWs micro-bolometer using heterogeneous integration.
• To evaluate the performance of the fabricated micro-bolometer for infrared imaging.
• To explore potential applications in commercial fields like medical diagnosis.

Main Methods:

• Fabrication of SiGe/Si MQWs micro-bolometer via heterogeneous integration using adhesive wafer bonding.
• Design and calculation of SiGe/Si MQWs infrared-absorption structure and thermal bridge.
• Fabrication of a 320 × 240 micro-bolometer array with 40 µm pitch L-type pixels.

Main Results:

• Achieved average infrared absorption efficiency exceeding 90% for wavelengths of 8-14 µm.
• Measured thermal properties: thermal capacity (1.043 × 10^-9 J/K), thermal conductivity (1.645 × 10^-7 W/K), and thermal time constant (7.25 ms).
• Recorded a total temperature coefficient of resistance (TCR) of 2.91%/K at 0.3 V bias.

Conclusions:

• The developed SiGe/Si MQWs micro-bolometer demonstrates high performance through heterogeneous integration.
• The material and fabrication approach enable advanced infrared imaging capabilities.
• Potential for widespread commercial applications, particularly in early medical diagnosis and biological detection.