Polysilicon metal-semiconductor-metal photodetectors for 1550 nm light.

摘要

Metal-semiconductor-metal (MSM) photodiodes are attractive in optoelectronic integrated circuits, as a result of their ease of integration into silicon CMOS technologies. 1550 nm is the wavelength of choice in long-haul telecommunications due to the low absorption and low dispersion of optical fiber at this wavelength. Demonstration of CMOS-compatible MSM devices operating at 1550 nm is the goal of this thesis.; MSM photodiodes were fabricated on polysilicon deposited by a variety of techniques. The highest responsivity obtained at 1550 nm was 0.34 mA/W. Dark currents were relatively high perhaps due to poor passivation of grain boundary states or surface roughness. It was found that polysilicon with grain sizes between 6 nm and 13 nm provides the best photoresponse at 1550 nm.; Attempts were also made to fabricate Germanium MSM photodetectors. Unfortunately, all of these devices had very high dark currents, so that no measurable photoresponse was obtained at 1550 nm.