Integration of waveguides and photodetectors in SiGe for 1.3 /spl mu/m operation

Splett, A.; Zinke, T.; Petermann, K.; Kasper, E.; Kibbel, H.; Herzog, H.‐J.; Presting, H.

doi:10.1109/68.265889

Cited by 73 publications

(24 citation statements)

References 7 publications

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“…850 nm) but in regimes with absorption depths larger than one micrometer either the speed requirements have to be reduced (10 GHz) or the responsivity for high speed applications (40-80 GHz) is below the ideal one. For this case lateral incidence devices offer advantages because absorption lengths and carrier transport lengths are decoupled allowing an optimization of both [11].…”

Section: Resultsmentioning

confidence: 99%

High speed germanium detectors on Si

Kasper

Oehme²

2008

Phys. Status Solidi (c)

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All the common group IV semiconductors – diamond, silicon carbide, silicon, germanium‐ are indirect semiconductors which narrows their optoelectronic application width. Silicon itself has a room temperature band gap of 1.12 eV with the first direct transition at 3.4 eV delivering strong absorption in the ultraviolet and the weaker indirect absorption in the visible up to the near infrared λ = 1.1 µm. Ge has a smaller bandgap (0.66 eV) which correlates with a larger band to band absorption limit (1.9 eV) but even more important the direct transition (0.8 eV) comes down to only about 150 meV above the indirect one. The speed of photodetectors is limited by two main factors, the carrier transport within the device and the RC time constant from loading the depletion layer capacitance via the external supply. High speed operation is obtained with absorption in the depletion layer where high electric fields accelerate the carriers to saturation velocity and avoiding slow carrier diffusion. In a pin diode structure this is obtained by sharp doping profiles (orders of magnitude increase/decrease within several Nanometers) and by the misfit dislocation network of the virtual substrate blocking diffusion from below the device. Indeed within a very short time the bandwidth of Ge on Si detectors was shifted in the GHz regime. The operation bias is usually in the reverse direction, but our group demonstrated also high speed (25 GHz) with zero bias when dark currents should be minimized. These photodetectors are sensitive in a broad spectral range (from visible to 1.6 µm). The lower limit is given by the absorption in the cap layer; the upper limit is the direct absorption edge of Ge. Silicon on insulator (SOI) optical waveguide system concept is explained which uses a light signal externally coupled in the silicon circuit. For its simplicity we propose a silicon on insulator (SOI) substrate. Rectangular waveguides like rib or ridge waveguides provide strong optical confinement at low device fabrication requirements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Resultsmentioning

confidence: 99%

High speed germanium detectors on Si

Kasper

Oehme²

2008

Phys. Status Solidi (c)

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“…The dark current density of this device at a reverse bias of 5 V is below 1 . 103A/crn2 [24]. Such a high dark current density does not seem inherent in SiGe/Si-superlattices, since in [9] a dark current density of 8 .…”

Section: Fabricated Devices 41 Sigewaveguide Detector Integrationmentioning

confidence: 93%

<title>Integrated optoelectronic waveguide detectors in SiGe for optical communications</title>

et al. 1995

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“…Alternatively, polyimide waveguides can be used to direct light to an array of MSM photodiodes [81]. Most approaches, however, employ a form of evanescent coupling between a transparent waveguide layer and an absorbing photodetector: coupling between InGaAsP and InGaAs [82], SiON and a-Si [83], and SiGe and a stack of SiGe quantum wells [84] have been demonstrated. In addition, Si technology easily allows monolithic integration of a photodetector with a silicon-based waveguide [61].…”

Section: Photodetector Integrationmentioning

confidence: 99%

Semiconductor Optical Sensors

Zappe

1999

Sensors Update

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Integration of waveguides and photodetectors in SiGe for 1.3 /spl mu/m operation

Cited by 73 publications

References 7 publications

High speed germanium detectors on Si

High speed germanium detectors on Si

<title>Integrated optoelectronic waveguide detectors in SiGe for optical communications</title>

Semiconductor Optical Sensors

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