ARCH-Type Microcantilever FPA for uncooled IR Detection M. Steffanson, K. Gorovoy, J. Król, V. Ramkiattisak, H. Hartmann, T. Ivanov and I.W. Rangelow Introduction: Seeing ‘heat‘ and visualizing beyond the visible band is a crucial application in many industries such as safety, security and quality assurance. hardly accessible to many applications due to high cost Current technologies for infrared (IR) detection are . Therefore our effort focuses on developing a low cost, mass-produced, high-performance uncooled thermal detector. Read-Out and Characterization: The microcantilevers are characterized for resonant frequency and IR sensitivity with a laser read-out. Theoretical predictions point out a <50mK noise equivalent temperature difference (NETD) for an optical read-out. Latest Development: Ready for Imaging Our latest developments include the fabrication of several designs of microcantilever FPAs of different sizes, such as 10x10, 60x60, 160x120, 320x240 and ultimately 640x480. Best performance design properties include: 55μm pitch · · 180nm/K deflection IR-sensitivity 12,5kHz resonant frequency 15ms thermal time constant · · Design Evaluation: Result: ARCH-type cantilevers have 5 major advantages in contrast to „sandwich-type“ cantilever IR-systems: 1. Low-cost fabrication due to a simple design and process flow with standard MEMS technology 2. No Read-Out-IC-wafer requirement - no electronics on sensor-chip at optical readout 3. Low thermo-mechanical noise due to ARCH-type cantilevers‘ high resonant frequency (up to 70kHz) 4. Great potential for higher sensitivity due to easily adjustable thermal isolation 5. Three options on read-out techniques depending on costs, application and sensitivity requirements The FPA is ready for a high-sensitive, high-performance and low-cost IR camera. Acknowledgement: This project was funded by Bundesministerium für Bildung und Forschung (BMBF) 03FO2272. Functional Principle: The so called ARCH-type microcantilever is a free standing construct consisting of two spatially separated (=„non-sandwich“) thin films with a mismatch of thermal expansion coefficients (CTE). At IR absorption ( P) the structure's temperature changes ( T) and due to the bimetallic effect it deflects ( z). All parameters have proportional interrelations: Δ Δ Δ Ilmenau University of Technology Tradition | Experience | An Eye to the Future C o n t a c t I N F O www.tu-ilmenau.de Ilmenau University of Technology Dept. of Microelectronic and Nanoelectronic Systems Prof. Ivo W. Rangelow | Tel.: +49 3677 69-3718 E-mail: [email protected] PO-BOX 100565, 98684 Ilmenau, Germany Deflection analysis with numerical simulations IR cameras make ‘heat‘ visible Detail of large scale FPA IR-sensing cantilevers have high homogeneity ARCH-type cantilever with sub-50μm pitch Experimental read-out set-up Resonant frequency and IR-sensitivity analysis 640x480 FPA sensor (=1x1in²) ready for IR camera Deflection is higher at ARCH-type cantilever design (left) compared to „sandwich-type“ design (right)

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ARCH-Type Microcantilever FPA for uncooled IR Detection

M. Steffanson, K. Gorovoy, J. Król, V. Ramkiattisak, H. Hartmann, T. Ivanov and I.W. Rangelow

Introduction:Seeing ‘heat‘ and visualizing beyond the visible band is a crucial application in many industries such assafety, security and quality assurance. hardlyaccessible to many applications due to high cost

Current technologies for infrared (IR) detection are. Therefore our effort focuses on developing a low cost,

mass-produced, high-performance uncooled thermal detector.

Read-Out and Characterization:The microcantilevers are characterized for resonant frequency and IR sensitivitywith a laser read-out.Theoretical predictions point out a <50mK noise equivalent temperature difference(NETD) for an optical read-out.

Latest Development: Ready for ImagingOur latest developments include the fabrication of several designs ofmicrocantilever FPAs of different sizes, such as 10x10, 60x60, 160x120, 320x240and ultimately 640x480. Best performance design properties include:

55μm pitch

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180nm/K deflection IR-sensitivity12,5kHz resonant frequency15ms thermal time constant�

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Design Evaluation:Result: ARCH-type cantilevers have 5 major advantages in contrast to „sandwich-type“ cantilever IR-systems:1. Low-cost fabrication due to a simple design and process flow with standard MEMS technology2. No Read-Out-IC-wafer requirement - no electronics on sensor-chip at optical readout3. Low thermo-mechanical noise due to ARCH-type cantilevers‘ high resonant frequency (up to 70kHz)4. Great potential for higher sensitivity due to easily adjustable thermal isolation5. Three options on read-out techniques depending on costs, application and sensitivity requirements

The FPA is ready for a high-sensitive, high-performance and low-cost IR camera.

Acknowledgement: This project was funded by Bundesministerium für Bildung und Forschung (BMBF) 03FO2272.

Functional Principle:The so called ARCH-type microcantilever is a freestanding construct consisting of two spatiallyseparated (=„non-sandwich“) thin films with amismatch of thermal expansion coefficients (CTE). At IRabsorption ( P) the structure's temperature changes( T) and due to the bimetallic effect it deflects ( z). Allparameters have proportional interrelations:

Δ Δ

Ilmenau University of Technology

Tradition | Experience | An Eye to the Future

C o n t a c t I N F O

www.tu-ilmenau.de

Ilmenau University of Technology

Dept. of Microelectronic and Nanoelectronic Systems

Prof. Ivo W. Rangelow | Tel.: +49 3677 69-3718

E-mail: [email protected]

PO-BOX 100565, 98684 Ilmenau, Germany

Deflection analysis with numerical simulations

IR cameras make ‘heat‘ visible