Pixel-level optical elements for uncooled infrared detector devices

An uncooled infrared detector element, comprising:

• a substrate;
• a microbolometer pixel membrane structure configured to absorb infrared radiation, the microbolometer pixel membrane structure comprising a membrane material supported at a position spaced above the substrate;
• a monolithically fabricated optical element suspended over and above the membrane material of the microbolometer pixel membrane structure, the monolithically fabricated optical element being structurally attached by an optical element support interconnect to an electrically conductive interconnect of the detector element;
• and
• one or more radiation detectors provided within or below the substrate and a reflector layer disposed on an upper surface of the substrate between the substrate and the microbolometer pixel structure, one or more openings being defined in the reflector layer corresponding to and vertically aligned with the one or more radiation detectors;
• wherein one or more openings are defined in the membrane structure corresponding to and vertically aligned with the one or more openings defined in the reflector layer;
• and wherein the optical element comprises one or more microlenses that are each configured to focus radiation onto a corresponding one of the radiation detectors through a corresponding opening in the membrane structure and a corresponding opening in the reflector layer.

A focal plane array assembly, comprising:

• a plurality of uncooled infrared detector elements arranged as an array, each of the plurality of uncooled infrared detector elements comprising:
• a substrate including read out integrated circuitry (ROIC), and
• a microbolometer pixel membrane structure configured to absorb infrared radiation, the microbolometer pixel membrane structure comprising an electrically conductive membrane material supported at a position spaced above the substrate by at least two spaced electrically conductive interconnects electrically coupled to the ROTC;
• where at least a portion of the plurality of uncooled infrared detector elements of the array further comprise a monolithically fabricated optical element suspended over and above the membrane material of the microbolometer pixel membrane structure by at least two optical element support interconnects that are at least partially aligned to and supported by the at least two electrically conductive interconnects.

A method of making a focal plane array assembly, comprising:

• providing a substrate;
• forming read out integrated circuitry (ROIC) for the substrate;
• forming a plurality of uncooled infrared detector elements arranged as an array, each of the plurality of uncooled infrared detector elements comprising:
• a substrate including read out integrated circuitry (ROIC);
• and
• a microbolometer pixel membrane structure configured to absorb infrared radiation, the microbolometer pixel membrane structure comprising an electrically conductive membrane material supported at a position spaced above the substrate by at least two spaced electrically conductive interconnects electrically coupled to the ROIC, the microbolometer pixel membrane structure having a thermal mass value;
• and
• monolithically fabricating an optical element suspended over and above the membrane material of the microbolometer pixel membrane structure of at least a portion of the plurality of uncooled infrared detector elements of the array by at least two optical element support interconnects that are at least partially aligned to and supported by the at least two electrically conductive interconnects.

An uncooled infrared detector element, comprising:

• a substrate;
• a microbolometer pixel membrane structure configured to absorb infrared radiation, the microbolometer pixel membrane structure comprising a membrane material supported at a position spaced above the substrate;
• a monolithically fabricated optical element suspended over and above the membrane material of the microbolometer pixel membrane structure;
• one or more radiation detectors provided within or below the substrate and a reflector layer disposed on an upper surface of the substrate between the substrate and the microbolometer pixel structure, one or more openings being defined in the reflector layer corresponding to and vertically aligned with the one or more radiation detectors;
• wherein one or more openings are defined in the membrane structure corresponding to and vertically aligned with the one or more openings defined in the reflector layer;
• and
• wherein the optical element comprises one or more microlenses that are each configured to focus radiation onto a corresponding one of the radiation detectors through a corresponding opening in the membrane structure and a corresponding opening in the reflector layer.

A focal plane array of uncooled infrared detector elements, comprising:

• a substrate;
• and
• a plurality of uncooled infrared detector elements, each of the plurality of infrared detector elements comprising:
• a microbolometer pixel membrane structure configured to absorb infrared radiation, the microbolometer pixel membrane structure comprising a membrane material supported at a position spaced above the substrate, and
• a monolithically fabricated optical element suspended over and above the membrane material of the microbolometer pixel membrane structure, the monolithically fabricated optical element being structurally attached by an optical element support interconnect to an electrically conductive interconnect of the detector element,
• wherein the membrane material comprises electrically conductive material;
• wherein the membrane material is supported at a position spaced above the substrate by at least two spaced electrically conductive interconnects;
• and wherein the monolithically fabricated optical element is suspended over and above the membrane material of the microbolometer pixel membrane structure by at least two optical element support interconnects that are at least partially aligned to and supported by the at least two electrically conductive interconnects.