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12 June 2001 Process development of fast and sensitive polySiGe microbolometer arrays
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Proceedings Volume 4288, Photodetectors: Materials and Devices VI; (2001)
Event: Symposium on Integrated Optics, 2001, San Jose, CA, United States
Extremely thin (50-100nm) polycrystalline silicon germanium (poly SiGe) microbolometers have been realized thanks to structural stiffness enhancement techniques within the pixel and the support legs. The technique involves the definition of U-shaped profiles using surface micromachining. This approach allows to decouple thermal isolation to some extent from thermal time constant. The result is a faster yet sensitive microbolometer compared to its thicker counterparts. Thermal time constants between 5 and 10 ms are achieved in vacuum yet the thermal conductance of the support legs is as low as the radiation limit (3x10-8 W/K). Apart from the (CMOS compatible) absorber definition and the release of the sacrificial oxide layer, the microbolometer process runs in a 8' Si CMOS pilot line and uses deep submicron stepper capability of the pilot line. The release process using vapor HF does not attack pixel, absorber or metal interconnect and leads to a yield close to or equal to 100%. Linear arrays and small 2D arrays of such microbolometers are demonstrated. To protect the bolometers in an early stage of the packaging, a zero-level (on-chip) flip-chip package based on indent-reflow sealing has been developed. The germanium window material is processed using process steps from multi-chip-module technology.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Piet De Moor, Spyros Kavadias, Vladimir Nikolaevic Leonov, and Chris A. Van Hoof "Process development of fast and sensitive polySiGe microbolometer arrays", Proc. SPIE 4288, Photodetectors: Materials and Devices VI, (12 June 2001);

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