Microbolometer uncooled infrared camera with 20-mK NETD

Radford, W. A.; Wyles, Richard; Wyles, Jessica; Varesi, J. B.; Ray, Michael; Murphy, Daniel F.; Kennedy, Adam; Finch, A.; Moody, Edgar A.; Cheung, Fred; Coda, R.; Baur, Stefan T.

doi:10.1117/12.317595

Cited by 19 publications

(6 citation statements)

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“…This represents approximately one order of magnitude lower thermal mass than obtained in our previous microbolometer structures, mainly due to the elimination of the supporting membrane. The value obtained here is also much smaller than that reported in conjunction with VO , Pt and Poly-Si-Ge microbolometers [8], [12], [13], [15], [16]. The absorptivity was calculated to be 30% for MM1 and 37% for MM2 from the fitted value and the measured by Joule heating.…”

Section: Measurements and Resultscontrasting

confidence: 60%

“…The thermal mass and the thermal mass per unit area of the 200-Å-thick platinum bolometers on 3000-to 5000-Å-thick SiN membranes were measured to be 1.7 10 J/K and 6.9 10 J/K-cm , respectively [15]. The thermal mass and thermal mass per unit area for a 500-Å-thick VO microbolometer on 5000-Å thick SiN was less than 1 10 J/K and 4 10 J/K-cm , respectively [8], [16]. The thermal mass and thermal mass per unit area for a 5000-Å-thick poly-SiGe microbolometer with a 1000 Å SiN absorber layer was observed to be 6.…”

Section: Introductionmentioning

confidence: 95%

“…The sensing thermometer is deposited on top of the microbridge. Several materials have been used as the thermometer such as VO [2], [8], poly-Si-Ge [12], [13], or metal resistors such as, titanium [11], and niobium [14]. A wide variety of sacrificial layers can be employed in micromachining.…”

Section: Introductionmentioning

confidence: 99%

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Self-supporting uncooled infrared microbolometers with low-thermal mass

Almasri

Butler²,

Çelik‐Butler³

2001

J. Microelectromech. Syst.

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A new micromachined microbolometer array structure is presented that utilizes a self-supporting semiconducting yttrium barium copper oxide (Y-Ba-Cu-O) thin film thermometer. The Y-Ba-Cu-O thermometer is held above the substrate only by the electrode arms without the need of any underlying supporting membrane. This represents a significant improvement in the state-of-the-art for microbolometers by eliminating the thermal mass associated with the supporting membrane. The reduced thermal mass permits lowering the thermal conductance to the substrate to obtain increased responsivity or having a shorter thermal time constant to allow for higher frame rate camera. The simple structure does not suffer from warping problems associated with stress imbalances in multilayer microbolometer structures that utilize a supporting membrane such as Si 3 N 4 . Devices were fabricated by growing Y-Ba-Cu-O films on a conventional polyimide sacrificial layer mesa. Subsequent etching of the sacrificial layer provides the air gap that thermally isolates the microbolometer. Y-Ba-Cu-O possesses a relatively high temperature coefficient of resistance of 3.1%/K at room temperature. The 400-nm-thick Y-Ba-Cu-O film exhibited absorptivity of about 30%. The responsivity and detectivity approached 10 4 V/W and 10 8 cm Hz 1 2 /W to filtered blackbody infrared (IR) radiation covering the 2.5 to 13.5 m band. This extrapolates to noise equivalent temperature difference (NETD) less than 100 mK. The micromachining techniques employed are post-complementary metal-oxide-semiconductor (CMOS) compatible, allowing for the fabrication of focal plane arrays for IR cameras.[649]Index Terms-Microbolometers, micromachining, uncooled infrared detection, yttrium barium copper oxide.

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Section: Measurements and Resultscontrasting

confidence: 60%

Section: Introductionmentioning

confidence: 95%

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Self-supporting uncooled infrared microbolometers with low-thermal mass

Almasri

Butler²,

Çelik‐Butler³

2001

J. Microelectromech. Syst.

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show abstract

“…Bolometers are a type of thermal detector in which the incident radiation is absorbed and converted to heat, resulting in temperature variation and thus the bolometer's electrical resistance change, this change can be detected by monitoring a bias current. Bolometric thermal detectors have been widely used in various applications [1][2][3][4] ranging from thermal imaging, radiation temperature measurement to night vision, aerial navigation. In traditional bolometers, the incident radiation power is converted to heat by additional integrated absorbers that are bulky (compared to the operating wavelength) and generally have a flat broadband spectral response 5,6 .…”

Section: Introductionmentioning

confidence: 99%

“…This change can be detected by monitoring a bias current. Bolometric thermal detectors have been widely used in various applications 1–4 ranging from thermal imaging and radiation temperature measurement to night vision and aerial navigation. In traditional bolometers, the incident radiation power is converted to heat by additional integrated absorbers that are bulky (compared to the operating wavelength) and generally have a flat broadband spectral response.…”

Section: Introductionmentioning

confidence: 99%