Optimization of high-speed metal-semiconductor-metal photodetectors

Circular-aperture Metal-Semiconductor-Metal (MSM) photodetectors have been fabricated in order to decrease the device capacitance. The frequency-response of the MSM photodetectors has been calculated using a first-order approximation. The design of the circular-aperture detectors and conventional square-aperture detectors has been optimized using this approximation. The largest 3 dB bandwidths are obtained with 33 fingers for the circular detectors and 29 for the square detectors. These numbers do not change regardless of the size of the MSM photodetectors.<
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