Resonant-cavity-enhanced high-speed Si photodiode grown by epitaxial lateral overgrowth

Schaub, J.D.; Li, R.; Schow, Clint L.; Campbell, Joe C.; Neudeck, G.W.; Denton, J.P.

doi:10.1109/68.806875

Cited by 51 publications

(21 citation statements)

References 12 publications

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“…The devices maintain efficiencies greater than 20% up to λ = 1200 nm, before the efficiency (responsivity) drops sharply to η = 3.4% (0.036 A/W) at λ = 1300 nm. The magnitude of the resonance effects observed for the Ge-on-SOI devices is considerably less than that occurring in the resonant-cavity Si detectors [27]. The results of our calculation for detectors using a 120-nm SiN x ARC show that the resonances can be nearly eliminated, while the quantum efficiency can be improved to η = 78%.…”

Section: DC Characteristicssupporting

confidence: 50%

“…Schaub et al [27] reported an example of such detectors that utilized Si laterally grown over a Si/SiO 2 Bragg reflecting mirror stack. These devices produced a −3-dB bandwidth of 34 GHz, while displaying high quantum efficiency (up to η = 42%) at wavelengths corresponding to sharp resonance peaks in the responsivity.…”

Section: Soi Detectorsmentioning

confidence: 99%

“…The resonant-cavity detector design [24] is another technique that can be applied to Si detectors [25]- [27] to improve efficiency while maintaining a thin absorbing layer. Schaub et al [27] reported an example of such detectors that utilized Si laterally grown over a Si/SiO 2 Bragg reflecting mirror stack.…”

Section: Soi Detectorsmentioning

confidence: 99%

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Germanium-on-SOI Infrared Detectors for Integrated Photonic Applications

Koester

Schaub²,

Dehlinger

et al. 2006

IEEE J. Select. Topics Quantum Electron.

147

115

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Abstract-An overview of recent results on high-speed germanium-on-silicon-on-insulator (Ge-on-SOI) photodetectors and their prospects for integrated optical interconnect applications are presented. The optical properties of Ge and SiGe alloys are described and a review of previous research on SOI and SiGe detectors is provided as a motivation for the Ge-on-SOI detector approach. The photodetector design is described, which consists of lateral alternating p-and n-type surface contacts on an epitaxial Ge absorbing layer grown on an ultrathin-SOI substrate. When operated at a bias voltage of −0.5 V, 10 µm ×10 µm devices have dark current I dark , of only ∼10 nA, a value that is nearly independent of finger spacing S, between S = 0.3 µm and 1.3 µm. Detectors with S = 1.3 µm have external quantum efficiencies η, of 52% (38%) at λ = 895 nm (850 nm) with corresponding responsivities of 0.38 A/W (0.26 A/W). The wavelength-dependence of η agrees fairly well with expectations, except at longer wavelengths, where Si up-diffusion into the Ge absorbing layer reduces the efficiency. Detectors with 10 µm ×10 µm area and S = 0.6 µm have −3-dB bandwidths as high as 29 GHz, and can simultaneously achieve a bandwidth of 27 GHz with I dark = 24 nA, at a bias of only −1 V, while maintaining high efficiency of η = 46%(33%), at λ = 895 nm (850 nm). Analysis of the finger spacing and areadependence of the device speed indicates that the performance at large finger spacing is transit-time-limited, while at small finger spacing, RC delays limit the bandwidth. Methods to improve the device performance are presented, and it is shown that significant improvement in the speed and efficiency both at λ = 850 and 1300 nm can be expected by optimizing the layer structure design.

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Section: DC Characteristicssupporting

confidence: 50%

Section: Soi Detectorsmentioning

confidence: 99%

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Germanium-on-SOI Infrared Detectors for Integrated Photonic Applications

Koester

Schaub²,

Dehlinger

et al. 2006

IEEE J. Select. Topics Quantum Electron.

147

115

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“…Photodiodes fabricated on this device layer typically suffered from high dark currents. Schaub et al, 13 has reported Si RCE photodiodes with low dark currents that achieved a bandwidth in excess of 34 GHz-the highest speed recorded for Si p-i-n photodiodes. These RCE structures used a merged epitaxial layer overgrowth ͑MELO͒ process to form the absorption region on top of the buried DBR.…”

Section: 4mentioning

confidence: 99%

High-speed Si resonant cavity enhanced photodetectors and arrays

Ünlü

Emsley

Dosunmu

et al. 2004

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Over the past decade a new family of optoelectronic devices has emerged whose performance is enhanced by placing the active device structure inside a Fabry-Perot resonant microcavity ͓P. E. Green, IEEE Spectrum 13 ͑2002͔͒. The increased optical field allows photodetectors to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. We have demonstrated a variety of resonant cavity enhanced ͑RCE͒ photodetectors in compound semiconductors ͓B. Yang, J. D. Schaub, S. M. Csutak, D. J. Rogers, and J. C. Campbell, IEEE Photonics Technol. Lett. 15, 745 ͑2003͔͒ and Si ͓M. K. Emsley, O. I. Dosunmu, and M. S. Ü nlü, IEEE J. Selected Topics Quantum Electron. 8, 948 ͑2002͔͒, operating at optical communication wavelengths ranging from 850 nm to 1550 nm. The focus of this article is on Si photodetectors and arrays. High bandwidth short distance communications standards are being developed based on parallel optical interconnect fiber arrays to meet the needs of increasing data rates of interchip communication in modern computer architecture. To ensure that this standard becomes an attractive option for computer systems, low cost components must be implemented on both the transmitting and receiving end of the fibers. To meet this low cost requirement silicon based receiver circuits are the most viable option, however, high speed, high efficiency silicon photodetectors present a technical challenge. Commercially reproducible silicon wafers with a high reflectance buried distributed Bragg reflector ͑DBR͒ have been designed and fabricated ͓M. K. Emsley, O. I. Dosunmu, and M. S. Ü nlü, IEEE J. Selected Topics Quantum Electron. 8, 948 ͑2002͔͒. The substrates consist of a two-period, 90% reflecting, DBR fabricated using a double silicon-on-insulator ͑SOI͒ process. Resonant-cavity-enhanced ͑RCE͒ Si photodetectors have been fabricated with 40% quantum efficiency at 850 nm and a FWHM of 29 ps suitable for 10 Gbps data communications. Recently, 1ϫ12 photodetector arrays have been fabricated, packaged, and tested with silicon based amplifiers to demonstrate the feasibility of a low cost solution for optical interconnects.

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“…As a result, silicon-based optoelectronics, photodetectors in particular, have received widespread attention. Although major strides have been made in designing Si-based photodetectors for short-haul (850 nm) operation, 1,2 long-haul operation based around the 1.3 -1.55 µm wavelength range still poses a great challenge. The complete transparency of silicon at wavelengths beyond 1.1 µm makes it unsuited for photodetection around the 1.3 -1.55 µm wavelength range.…”

Section: Introductionmentioning

confidence: 99%

Germanium on double-SOI photodetectors for 1550 nm operation

Dosunmu

Emsley

Cannon³

et al.

The 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2003. LEOS 2003.

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We have fabricated and characterized the first resonant cavity enhanced (RCE) germanium photodetectors on double silicon-on-insulator substrates (Ge/DSOI) for operation around the 1550 nm communication wavelength. The Ge layer is grown through a novel two-step UHV/CVD process, while the underlying double-SOI substrate is formed through an ion-cut process. Absorption measurements of an undoped Ge-on-Si (Ge/Si) structure reveal a red-shift of the Ge absorption edge in the NIR, due primarily to a strain-induced bandgap narrowing within the Ge film. By using the strained-Ge absorption coefficients extracted from the absorption measurements, in conjunction with the known properties of the DSOI substrate, we were able to design strained-Ge/DSOI photodetectors optimized for 1550 nm operation. We predict a quantum efficiency of 76% at 1550 nm for a Ge layer thickness of only 860 nm as a result of both strain-induced and resonant cavity enhancement, compared to 2.3% for the same unstrained Ge thickness in a single-pass configuration. We also estimate a transit-time limited bandwidth of 28 GHz. Although the fabricated Ge/DSOI photodetectors were not optimized for 1550 nm operation, we were able to demonstrate an over four-fold improvement in the quantum efficiency, compared to its single-pass counterpart.

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Resonant-cavity-enhanced high-speed Si photodiode grown by epitaxial lateral overgrowth

Cited by 51 publications

References 12 publications

Germanium-on-SOI Infrared Detectors for Integrated Photonic Applications

Germanium-on-SOI Infrared Detectors for Integrated Photonic Applications

High-speed Si resonant cavity enhanced photodetectors and arrays

Germanium on double-SOI photodetectors for 1550 nm operation

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