Teknologian Tutkimuskeskus Vtt Oy

Aapo Varpula

Mika Prunnila

Christer Holmlund

Kirsi Tappura

Anna Rissanen

Bin Guo

Kestutis Grigoras

An absorber structure for a thermal detector, the absorber structure including edges defining a basic form, a plurality of first legs of electrically conducting material joined in an electrically conductive manner to form, between the edges of the absorber structure, a grid having openings, the first legs forming at least one continuous connection between the edges of the absorber structure; and a plurality of second legs of electrically conducting material joined in an electrically conductive manner to the first legs, wherein the second legs protrude from the first legs into the openings of the grid and terminate at points of termination located at a distance from adjacent first legs.

Absorber structure for thermal detectors

A wafer-level integrated thermal detector comprises a first wafer and a second wafer (W, W) bonded together. The first wafer (W) includes a dielectric or semiconducting substrate (), a dielectric sacrificial layer () deposited on the substrate, a support layer () deposited on the sacrificial layer or the substrate, a suspended active element () provided within an opening () in the support layer, a first vacuum-sealed cavity () and a second vacuum-sealed cavity () on opposite sides of the suspended active element. The first vacuum-sealed cavity () extends into the sacrificial layer () at the location of the suspended active element (). The second vacuum-sealed cavity () comprises the opening of the support layer () closed by the bonded second wafer. The thermal detector further comprises front optics () for entrance of radiation from outside into one of the first and second vacuum-sealed cavities, aback reflector () arranged to reflect radiation back into the other one of the first and second vacuum-sealed cavities, and electrical connections () for connecting the suspended active element to a readout circuit ().

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Vtt, Finland

Aapo Varpula