DC and AC performance of leaky-mode metal-semiconductor-metal polysilicon photodetectors

Robert Pownall; Guangwei Yuan; Charles Thangaraj; Joel Kindt; Tom W. Chen; Phil Nikkel; Kevin L. Lear

doi:10.1117/12.843002

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25 February 2010 DC and AC performance of leaky-mode metal-semiconductor-metal polysilicon photodetectors

Robert Pownall, Guangwei Yuan, Charles Thangaraj, Joel Kindt, Tom W. Chen, Phil Nikkel, Kevin L. Lear

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Proceedings Volume 7598, Optical Components and Materials VII; 759811 (2010) https://doi.org/10.1117/12.843002
Event: SPIE OPTO, 2010, San Francisco, California, United States

Abstract

Metal-semiconductor-metal (MSM) polysilicon photodetectors which are compatible with all standard complementary metal-oxide-semiconductor (CMOS) processes and which were made in a commercial 0.35 ìm process have demonstrated DC responsivities up to 1.3 A/W at 690 nm. An effective absorption coefficient of 0.63 dB/ìm was found from a comparison of responsivities of 5- and 10-μm long detectors. For a constant bias voltage, responsivity varies as the inverse square of the contact spacing, with responsivity continuing to increase for the smallest available contact spacing devices. Responsivities corresponding to quantum efficiencies over 200% were observed, implying a gain mechanism. For AC performance, electrical pulse full-width at half-maximum (FWHM) as low as 0.81 ns and 10% - 90% rise times as low as 0.39 ns have been measured in response to ~0.65 ns FWHM optical input pulses. The ability to modulate the source laser diode limits the measured pulse performance of the detectors. Observed DC and pulse results are well explained by an analytic expression which incorporates the effects of bulk and contact recombination. Possible means of improving the detector speed are proposed.2

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Robert Pownall, Guangwei Yuan, Charles Thangaraj, Joel Kindt, Tom W. Chen, Phil Nikkel, and Kevin L. Lear "DC and AC performance of leaky-mode metal-semiconductor-metal polysilicon photodetectors", Proc. SPIE 7598, Optical Components and Materials VII, 759811 (25 February 2010); https://doi.org/10.1117/12.843002

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