Fabrication of a Photodetector Array on Thin Silicon

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. Bonds to ROIC Frontside (Bonds to Multiplexer) Backside (Collects Radiation) Top-Down Views Device Fabrication and Testing Cross-Sectional View 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. Frontside (Bonds to Multiplexer) Backside (Collects Radiation) Pattern Repeats (The lines visible here 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