High-performance uncooled digital 17 urn QVGA-IRFPA-using microbolometer based on amorphous silicon with massively parallel Sigma-Delta-ADC readout

摘要

This paper presents the results of a high-performance digital QVGA-IRFPA based on uncooled microbolometers with a pixel-pitch of 17 μm and a chip-scale-package as the vacuum package developed and fabricated by Fraunhofer-IMS. Due to a direct conversion of the microbolometer's resistance into a 16 bit value by the use of massively parallel on-chip Sigma-Delta-ADCs a high scene temperature dynamic range of more than 300 K and a very low NETD-value below 50 mK is achieved. Due to a broad-band antireflection coating the digital 17μm QVGA-IRFPA achieves a high sensitivity in the LW1R (wavelength 8 urn to 14 μm) and MWIR (wavelength 3 nm to 5 μm) range. In this paper the microbolometer, the vacuum-packaging, the architecture of the readout electronics, and the electro-optical performance characterization will be presented.