Precise annealing of focal plane arrays for optical detection
Precise annealing of identified defective regions of a Focal Plane Array (“FPA”) (e.g., exclusive of non-defective regions of the FPA) facilitates removal of defects from an FPA that has been hybridized and/or packaged with readout electronics. Radiation is optionally applied under operating conditions, such as under cryogenic temperatures, such that performance of an FPA can be evaluated before, during, and after annealing without requiring thermal cycling.
1. A method comprising:
receiving a Focal Plane Array (“FPA”) having an identified defective region, the defective region corresponding to at least one defective pixel, the defective region being less than an entirety of the FPA, wherein the FPA comprises a Read-Out Integrated Circuit (“ROIC”) layer hybridized with a sensor layer;
reading values from the ROIC layer under a dark condition; and
irradiating a portion of the FPA based upon the values read from the ROIC layer under the dark condition by irradiating the defective region to anneal the at least one defective region without annealing a non-defective region of the FPA, wherein irradiating the defective region comprises applying at least one of a laser beam or focused acoustical energy to the identified defective region.
2. The method of claim 1 , wherein the defective region is defective due to a defect in a PN junction within the sensor layer.
3. The method of claim 1 , wherein the sensor layer comprises material selected from a group comprising Si, HgCdTe, InSb, CdTe, or GaInAs.
4. The method of claim 1 , comprising:
before irradiating, identifying the defective region based upon a value corresponding to the at least one defective pixel read from the ROIC layer.
5. The method of claim 4 , wherein the identifying of defective region is based at least in part upon a baseline pixel performance map of the ROIC layer obtained prior to the ROIC layer being hybridized with the sensor layer.
6. The method of claim 1 , wherein the defective region is irradiated while the FPA is under thermal vacuum.
7. The method of claim 1 , wherein the defective region comprises at least one of a high dark current defect, a noise defect, a dislocation defect, operational wear-and-tear, or adversarial irradiation damage.
8. A method of manufacturing a Focal Plane Array (“FPA”), the method comprising:
hybridizing a sensor layer with a Readout Integrated Circuit (“ROIC”) layer to form the FPA, the FPA comprising an identified defective region, the defective region comprising at least one defective pixel, the defective region being less than an entirety of the FPA;
reading values from the ROIC layer when the FPA is under a dark condition;
identifying the at least one defective pixel based upon a value corresponding to the at least one defective pixel read from the ROIC layer; and
irradiating a portion of the FPA based upon the values read from the ROIC layer under the dark condition by irradiating the defective region to anneal the at least one defective pixel without annealing a non-defective region of the FPA, wherein irradiating the defective region comprises applying at least one of a laser beam or focused acoustical energy to the identified defective region.
9. The method of claim 8 , wherein the method is performed in a thermal vacuum.
10. The method of claim 8 , wherein the FPA comprises a sensor layer that is composed of HgCdTe.