Optoelectronic Simulation of the APRA Imaging Detector Tarun

Optoelectronic Simulation of the APRA Imaging Detector Tarun Parmar (RIT, Micro. E Co-op) Background • RIDL is designing and fabricating a very low noise hybrid CMOS imaging detector future NASA astrophysics and planetary space missions. • Accurate simulations and calculations of electron hole pair behaviour is necessary for optimization of the device design. Results • Simulated the electric field distribution in the photodiode • Simulated the recombination current of the photodiode • Calculated the recombination current for different cathode voltages Goals • Create a device model to optimize the detector design and the fabrication process Plan • Use Silvaco Athena model the fabrication of the imaging detector • Use Silvaco Atlas model the detector operation Device Operation anode p+ – intrinsic Figure 3: Simulation of the electric field around the P+ section of the photodiode V + n+ cathode Photons reach depletion region Figure 1: Diagram of a photodiode. Photodiodes consist of a PIN junction operated in reverse bias mode. + Produce e – h pairs Figure 2: Describes how the photodiode converts photons into a measurable current P-I-N photodiode operated in reverse Electric field sweeps charges across junction bias • P+ – high acceptor concentration • I-ntrinsic (lightly) doped material Movement of charge results in a small current • N+ –high donor concentration Mag. of this current a Incident light intensity Figure 4: Plot of recombination rate vs. cathode voltage