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Fabrication of a Photodetector Array on Thin Silicon Wafer
Kim Manser
RIDL (Rochester Imaging Detector Labs) is currently designing and fabricating a focal plane array that would be used on a satellite to capture images in space as
part of the Joint Dark Energy Mission, a portion of the Beyond Einstein initiative by NASA.
The device is made up of a detector (collects light and generates a current) and a readout circuit (translates the detector’s signals into image information) and
works like a CCD camera. When a photon is incident on the detector, it excites an electron, which is then freed from the silicon crystal lattice and carried to the
other side of the device (where the current is collected in localized areas called pixels) by an electric field. It uses this photovoltaic current as a signal for the
presence of light in the field of study, which is converted to an image by assembling these pixels in the correct order. This signal is then read by a readout
integrated circuit (ROIC) and sent to a processor that converts the digital information to an image.
The ROIC has been designed by a team headed by Dr. Zeljko Ignjatovic and the University of Rochester and is being fabricated by an outside facility. The detector
design is currently under fabrication here at RIT in the SMFL (Semiconductor and Microsystems Fabrication Laboratory), a class-100 clean room located in building
17, the Microelectronic Engineering department.
Bonds to ROIC
Cross-Sectional
View
Device Fabrication and
Testing
Frontside (Bonds to Multiplexer)
Backside (Collects Radiation)
Top-Down Views
Frontside (Bonds to Multiplexer)
Backside (Collects Radiation)
Pattern
Repeats
(The lines visible here are
actually passivated.)
Design Team: Director Dr. Don Figer, Dr. Jingjing Zhang, Dr. Zoran Ninkov
Simulations: Tarun Parmar, Dr. Jingjing Zhang, Kimberly Manser
Process Design and Fabrication: Kimberly Manser, Dr. Jingjing Zhang