An 850 nm SiGe/Si HPT with a 4.12 GHz maximum optical transition frequency and 0.805A/W responsivity

Tegegne, Zerihun Gedeb; Viana, Carlos; Rosales, Marc; Schiellein, Julien; Polleux, Jean-Luc; Grzeskowiak, Marjorie; Richalot, Elodie; Algani, Catherine

doi:10.1017/s1759078715001531

Cited by 9 publications

(4 citation statements)

References 17 publications

(27 reference statements)

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“…To locate the source of this extra photocurrent in the phototransistor structure and to study its impact on the optomicrowave (OM) behavior of the HPT, we performed a dc and an OM mapping of the devices using scanning nearfield optical microscopy (SNOM) with the measurement setup described in [18] and [19], where a 850-nm vertical cavity surface emitting laser (of 12-GHz cutoff frequency) is directly modulated to illuminate the HPT through a lensed MMF moved over the HPT surface. Fig.…”

Section: Experimental Results and Discussion A Substrate Photodmentioning

confidence: 99%

Intrinsic Frequency Response of Silicon–Germanium Phototransistor Associated With 850-nm Multimode Fiber

Tegegne

Viana

Grzeskowiak

et al. 2018

IEEE Trans. Electron Devices

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The intrinsic frequency response of silicongermanium heterojunction bipolar phototransistors (HPTs) at 850 nm is studied to be implemented in multimode fiber systems. The experimental analysis of an HPT with an optical window size of 10 × 10 µm 2 is presented. An optomicrowave (OM) scanning near-field optical microscopy is performed to observe the variation of the HPT dynamic behavior versus the illumination location of the phototransistor. The photocurrent generated by the photodiode at the interface between the n ++ subcollector and the p + guard ring is analyzed, and its impact on the performance of the HPT is investigated. Then, we propose a technique to remove the substrate photocurrent effect on the optical transition frequency (f Topt ): f Topt value of 4.1 GHz given by raw measurement results increases up to 6 GHz after removing the substrate response. The influence of the 2-D carrier flows on the HPT intrinsic OM behavior is also studied. Design aspects of SiGe/Si HPT structures are finally discussed as a conclusion.Index Terms-Microwave photonics, opto-microwave scanning near-field optical microscopy (OM-SNOM), siliconbased photodetectors, SiGe phototransistor, substrate effect.

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Section: Experimental Results and Discussion A Substrate Photodmentioning

confidence: 99%

Intrinsic Frequency Response of Silicon–Germanium Phototransistor Associated With 850-nm Multimode Fiber

Tegegne

Viana

Grzeskowiak

et al. 2018

IEEE Trans. Electron Devices

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“…This ensures the compatibility with the process technology and the potential integration of complete opto-electronic radio-frequency (OE-RF) circuits. The basic HPT structure is designed by extending the emitter, base and collector layers of the reference HBT [12] to provide an optical access as presented in Figure 2. This HPT is essentially one large HBT whose emitter metallization was put only on the side.…”

Section: Sige/si Hpt Structure Under Studymentioning

confidence: 99%

“…On-wafer bench setup described in [12] is used to measure the opto-microwave performances of top and edge side illuminated HPTs. An 850nm light source, which is directly modulated, illuminates the HPT through a lensed multimode fiber (MMF).…”

Section: On-wafer Opto-microwave Characterizationmentioning

confidence: 99%

Improving the opto-microwave performance of SiGe/Si phototransistor through edge-illuminated structure

et al. 2016

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This paper demonstrates the experimental study of edge and top illuminated SiGe phototransistors (HPT) implemented using the existing industrial SiGe2RF Telefunken GmbH BiCMOS technology for opto-microwave (OM) applications using 850nm Multi-Mode Fibers (MMF). Its technology and structure are described. Two different optical window size HPTs with top illumination (5x5µm 2 , 10x10µm 2) and an edge illuminated HPTs having 5µm x5µm size are presented and compared. A two-step post fabrication process was used to create an optical access on the edge of the HPT for lateral illumination with a lensed MMF through simple polishing and dicing techniques. We perform Opto-microwave Scanning Near-field Optical Microscopy (OM-SNOM) analysis on edge and top illuminated HPTs in order to observe the fastest and the highest sensitive regions of the HPTs. This analysis also allows understanding the parasitic effect from the substrate, and thus draws a conclusion on the design aspect of SiGe/Si HPT. A low frequency OM responsivity of 0.45A/W and a cutoff frequency, f-3dB , of 890MHz were measured for edge illuminated HPT. Compared to the top illuminated HPT of the same size, the edge illuminated HPT improves the f-3dB by a factor of more than two and also improves the low frequency responsivity by a factor of more than four. These results demonstrate that a simple etched HPT is still enough to achieve performance improvements compared to the top illuminated HPT without requiring a complex coupling structure. Indeed, it also proves the potential of edge coupled SiGe HPT in the ultra-low-cost silicon based optoelectronics circuits with a new approach of the optical packaging and system integration to 850nm MMF.

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“…However, due to the existence of junction capacitance and the slow-photon-generated carriers in the Si substrate, the working speed of the device is greatly limited. [7][8][9][10][11] To improve the working speed of the Si-based SiGe HPT, a buried oxide (BOX) layer is introduced into its collector in this paper. Due to the existence of series capacitance of BOX layer, the collector-substrate capacitance, the base-collector junction capacitance as well as the base-emitter junction capacitance are reduced to a certain degree.…”

Section: Introductionmentioning

confidence: 99%

Effects of buried oxide layer on working speed of SiGe heterojunction photo-transistor*

Liu¹,

Ma²,

Xie³

et al. 2020

Chinese Phys. B

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The effects of buried oxide (BOX) layer on the capacitance of SiGe heterojunction photo-transistor (HPT), including the collector–substrate capacitance, the base–collector capacitance, and the base–emitter capacitance, are studied by using a silicon-on-insulator (SOI) substrate as compared with the devices on native Si substrates. By introducing the BOX layer into Si-based SiGe HPT, the maximum photo-characteristic frequency f t,opt of SOI-based SiGe HPT reaches up to 24.51 GHz, which is 1.5 times higher than the value obtained from Si-based SiGe HPT. In addition, the maximum optical cut-off frequency f β,opt, namely its 3-dB bandwidth, reaches up to 1.13 GHz, improved by 1.18 times. However, with the increase of optical power or collector current, this improvement on the frequency characteristic from BOX layer becomes less dominant as confirmed by reducing the 3-dB bandwidth of SOI-based SiGe HPT which approaches to the 3-dB bandwidth of Si-based SiGe HPT at higher injection conditions.

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An 850 nm SiGe/Si HPT with a 4.12 GHz maximum optical transition frequency and 0.805A/W responsivity

Cited by 9 publications

References 17 publications

Intrinsic Frequency Response of Silicon–Germanium Phototransistor Associated With 850-nm Multimode Fiber

Intrinsic Frequency Response of Silicon–Germanium Phototransistor Associated With 850-nm Multimode Fiber

Improving the opto-microwave performance of SiGe/Si phototransistor through edge-illuminated structure

Effects of buried oxide layer on working speed of SiGe heterojunction photo-transistor*

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