Bolometer having absorber with pillar structure for thermal shorting

A method of operating a semiconductor device, the method comprising:

• measuring a first electrical resistance in an absorber structure of a bolometer device formed on a substrate, the absorber structure being suspended over an electrode structure provided on an upper surface of the substrate and spaced a first distance apart from the electrode structure, the absorber structure including i) suspension structures extending upwardly from the substrate and being electrically connected to readout conductors on the upper surface of the substrate, and ii) a pillar structure extending downwardly from the absorber structure toward the electrode structure, the pillar structure having a contact portion located a second distance apart from the first electrode structure, the second distance being less than the first distance, the absorber structure being configured to flex toward the substrate in response to a test condition, the second distance being selected such that the contact portion of the pillar structure is positioned in contact with the electrode structure when the absorber structure is flexed in response to the test condition, the first electrical resistance being measured with the contact portion of the pillar structure spaced apart from the electrode structure;
• applying the test condition to the absorber structure after the first electrical resistance is measured to flex the absorber structure and bring the contact portion of the pillar structure into contact with the electrode structure;
• and
• measuring a second electrical resistance in the absorber structure while the contact portion of the pillar structure is contacting the electrode structure.

A method of fabricating a semiconductor device, the method comprising:

• depositing a sacrificial layer stack over a patterned conductive layer provided on a surface of a substrate, the patterned conductive layer including an electrode structure, the sacrificial layer stack having an upper surface at a first distance above the electrode structure;
• patterning the sacrificial layer stack to include anchor holes that extend down from the upper surface of the layer stack to the patterned conductive layer;
• patterning the sacrificial layer stack to include a pillar hole that extends toward the electrode structure from the upper surface of the layer stack to a second distance apart from the electrode structure, the second distance being less than the first distance;
• depositing a conductive material onto the sacrificial layer stack to form an absorber structure, the conductive material lining walls of the anchor holes to form suspension structures that support the absorber structure at the first distance and lining walls of the pillar hole to form a pillar structure, the pillar structure having a contact portion located at the second distance;
• and
• configuring the absorber structure to flex toward the substrate in response to a test condition to bring the contact portion of the pillar structure into contact with the electrode structure.