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Fabrication of a Photodetector Array on Thin Silicon Wafer
Kim Manser (RIT, MicroE Co-Op)
Background
• RIDL is currently designing and fabricating a focal plane array that could be
used on future NASA astrophysics and planetary space missions.
• This detector does stuff that’s different than current detectors
Device Fabrication Flow Chart
Goals
• Kim is working on something towards the overall goal of making the detector
Plan
• Kim will do certain tasks to work towards completing the goal stated above
• …
Device Operation
• The device is made up of a detector (collects light and generates a current) and
the ROIC (to translate the detector’s signals into image information).
• When a photon is incident on the detector, it excites an electron-hole pair, which
are then freed from the silicon crystal lattice and carried to opposite sides of the
device (where the current is collected in localized areas called pixels).
• The detector ouput circuit converts the integrated charge into a voltage that
represents a signal that is proportional to light.
ROIC
n-Si
Bonds to ROIC
•Above is a flow chart of how this device will be fabricated
•The readout integrated circuit (ROIC) has been designed by a team
headed by Dr. Zeljko Ignjatovic at the University of Rochester and is
being fabricated by an outside facility.
•The detector design is currently under fabrication at RIT in the
Semiconductor and Microsystems Fabrication Laboratory, a class100 clean room.
p+ Si
Thermal oxide
LTO
Al
In
Cross-Sectional View
n+ Si
Section describing Kim’s work in the fabrication process
Photodetector
• Kim is working on the photodetector fabrication….
• She is modeling the fabrication process…
ROIC
Photodetector
photons