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Proceedings Paper

Process development of fast and sensitive polySiGe microbolometer arrays
Author(s): Piet De Moor; Spyros Kavadias; Vladimir Nikolaevic Leonov; Chris A. Van Hoof
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Paper Abstract

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.

Paper Details

Date Published: 12 June 2001
PDF: 6 pages
Proc. SPIE 4288, Photodetectors: Materials and Devices VI, (12 June 2001); doi: 10.1117/12.429397
Show Author Affiliations
Piet De Moor, IMEC (Belgium)
Spyros Kavadias, IMEC (Belgium)
Vladimir Nikolaevic Leonov, XenICs (Belgium)
Chris A. Van Hoof, IMEC (Belgium)


Published in SPIE Proceedings Vol. 4288:
Photodetectors: Materials and Devices VI
Gail J. Brown; Manijeh Razeghi, Editor(s)

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