• Title, Summary, Keyword: Photodetector

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High-Speed CMOS Binary Image Sensor with Gate/Body-Tied PMOSFET-Type Photodetector

  • Choi, Byoung-Soo;Jo, Sung-Hyun;Bae, Myunghan;Kim, Jeongyeob;Choi, Pyung;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.23 no.5
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    • pp.332-336
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    • 2014
  • In this paper, we propose a complementary metal oxide semiconductor (CMOS) binary image sensor with a gate/body-tied (GBT) PMOSFET-type photodetector for high-speed operation. The GBT photodetector of an active pixel sensor (APS) consists of a floating gate ($n^+$-polysilicon) tied to the body (n-well) of the PMOSFET. The p-n junction photodiode that is used in a conventional APS has a good dynamic range but low photosensitivity. On the other hand, a high-gain GBT photodetector has a high level of photosensitivity but a narrow dynamic range. In addition, the pixel size of the GBT photodetector APS is less than that of the conventional photodiode APS because of its use of a PMOSFET-type photodetector, enabling increased image resolution. A CMOS binary image sensor can be designed with simple circuits, as a complex analog to digital converter (ADC) is not required for binary processing. Because of this feature, the binary image sensor has low power consumption and high speed, with the ability to switch back and forth between a binary mode and an analog mode. The proposed CMOS binary image sensor was simulated and designed using a standard CMOS $0.18{\mu}m$ process.

High-Speed Traveling-Wave Photodetector with a 3-dB Bandwidth of 410 GHz

  • Park, Jeong-Woo;Han, Sangpil;Lee, Donghun;Ryu, Han-Cheol;Shin, Jun-Whan;Kim, Namje;Yoon, Young-Jong;Ko, Hyunsung;Park, Kyung Hyun
    • ETRI Journal
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    • v.34 no.6
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    • pp.942-945
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    • 2012
  • A high-speed traveling-wave photodetector (TWPD) with an InGaAs absorber is designed and realized. The bandwidth of the TWPD is measured using electro-optic sampling techniques. The bandwidth is 410 GHz, which shows that the RC limitation is overcome. While the TWPD shows a low responsivity of 0.06 A/W at 1,550 nm, this value can be improved through further optimization of the structure without a sacrifice in bandwidth.

Modeling of Gate/Body-Tied PMOSFET Photodetector with Built-in Transfer Gate (내장된 전송게이트를 가지는 Gate/Body-Tied PMOSFET 광 검출기의 모델링)

  • Lee, Minho;Jo, Sung-Hyun;Bae, Myunghan;Choi, Byoung-Soo;Choi, Pyung;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.23 no.4
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    • pp.284-289
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    • 2014
  • In this paper, modeling of a gate/body-tied (GBT) PMOSFET photodetector with built-in transfer gate is performed. It can control the photocurrent with a high-sensitivity. The GBT photodetector is a hybrid device consisted of a MOSFET, a lateral BJT, and a vertical BJT. This device allows for amplifying the photocurrent gain by $10^3$ due to the GBT structure. However, the operating parameters of this photodetector, including its photocurrent and transfer characteristics, were not known because modeling has not yet been performed. The sophisticated model of GBT photodetector using a process simulator is not compatible with circuit simulator. For this reason, we have performed SPICE modeling of the photodetector with reduced complexity using Cadence's Spectre program. The proposed modeling has been demonstrated by measuring fabricated chip by using 0.35 im 2-poly 4-metal standard CMOS technology.

Characteristics of a PMOSFET Photodetector for Highly-Sensitive Active Pixel Sensor (고감도 능동픽셀센서를 위한 PMOSFET 광검출기의 특성)

  • Seo, Sang-Ho;Park, Jae-Hyoun;Lee, June-Kyoo;Wang, In-Soo;Shin, Jang-Kyoo;Jo, Young-Chang;Kim, Hoon
    • Journal of Sensor Science and Technology
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    • v.12 no.4
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    • pp.149-155
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    • 2003
  • A PMOSFET photodetector for highly-sensitive active pixel sensor(APS) is presented. This sensor uses 5V power supply and has been designed and fabricated using I-poly and 2-metal $1.5{\mu}m$ CMOS technology. The feature of a PMOSFET photodetector is that the polysilicon gate of the PMOSFET was connected to n-well, in order to increase the photo sensitivity. The designed MOS photodetector has similar $I_{DS}-V_{DS}$ characteristics with a standard MOSFET. One dimensional image sensor with 16 pixels based on the PMOSFET photodetector has also been designed and fabricated. Unit pixel of the designed sensor consists of a PMOSFET photodetector and 4 NMOSFETs. Unit pixel area is $86{\mu}m{\times}90.5{\mu}m$ and its fill factor is about 12%.

Effects of Optically-modulated Metal-graphene Contact on the Photoresponsivity of Graphene Photodetectors (빛에 의해 변조되는 금속-그래핀 컨택이 그래핀 포토디텍터의 광응답도에 미치는 영향)

  • Lee, Chang-Ju;Shim, Jae Hoon;Park, Hongsik
    • Journal of Sensor Science and Technology
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    • v.28 no.2
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    • pp.117-120
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    • 2019
  • Graphene is recognized as a promising material for silicon photonics, since it has a wide optical-window that entirely covers the optical communication wavelength region ($1.3{\sim}1.6-{\mu}m$) and extremely high-carrier mobility that makes it possible to fabricate the high-speed photodetectors. However, the maximum absorbance of monolayer graphene is only 2.3%, which limits the photoresponse characteristics of graphene photodetectors. As a result, a low photoresponsivity of graphene photodetector is a critical issue limiting the use of graphene photodetectors in the optical communications field. In this paper, we investigated effects of optically-modulated metal-graphene contact on the photoresponsivity of graphene photodetectors. The optical modulation of the contact resistance mainly determined the photoresponse characteristics of graphene photodetectors. The Ni-contact graphene photodetector which has a characteristic of the significant optical modulation of metal-graphene contact showed a higher photoresponsivity than the Pd-contact device. This work will provide a way to improve the photoresponse characteristics of graphene-based photodetector and contribute to the development of high-speed/high-responsivity graphene photodetector.

CMOS Binary Image Sensor with Gate/Body-Tied PMOSFET-Type Photodetector for Low-Power and Low-Noise Operation

  • Lee, Junwoo;Choi, Byoung-Soo;Seong, Donghyun;Lee, Jewon;Kim, Sang-Hwan;Lee, Jimin;Shin, Jang-Kyoo;Choi, Pyung
    • Journal of Sensor Science and Technology
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    • v.27 no.6
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    • pp.362-367
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    • 2018
  • A complementary metal oxide semiconductor (CMOS) binary image sensor is proposed for low-power and low-noise operation. The proposed binary image sensor has the advantages of reduced power consumption and fixed pattern noise (FPN). A gate/body-tied (GBT) p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET)-type photodetector is used as the proposed CMOS binary image sensor. The GBT PMOSFET-type photodetector has a floating gate that amplifies the photocurrent generated by incident light. Therefore, the sensitivity of the GBT PMOSFET-type photodetector is higher than that of other photodetectors. The proposed CMOS binary image sensor consists of a pixel array with $394(H){\times}250(V)$ pixels, scanners, bias circuits, and column parallel readout circuits for binary image processing. The proposed CMOS binary image sensor was analyzed by simulation. Using the dynamic comparator, a power consumption reduction of approximately 99.7% was achieved, and this performance was verified by the simulation by comparing the results with those of a two-stage comparator. Also, it was confirmed using simulation that the FPN of the proposed CMOS binary image sensor was successfully reduced by use of the double sampling process.

SnS-embedded High Performing and Transparent UV Photodetector (SnS 기반의 고성능 투명 UV 광검출기)

  • Park, Wang-Hee;Ban, Dong-Kyun;Kim, Hyunki;Kim, Hong-Sik;Patel, Malkeshkumar;Yoo, Jeong Hee;Kim, Joondong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.7
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    • pp.445-448
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    • 2016
  • Transparent UV photodetector was achieved by using wide bandgap metal oxide materials. In order to realize transparent heterojunction UV photodetector, n-type ZnO and p-type NiO metal oxide materials were employed. High light-absorbing SnS layer was inserted into the n-ZnO and p-NiO layers. High-performing UV photodetector was realized by ZnO/SnS/NiO/ITO structures to provide extremely fast response times (Fall time: $7{\mu}s$ and rise time: $13{\mu}s$) and high rectifying ratio. The use of functional SnS-embedded photodetector would provide a route for high functional photoelectric devices.

Analysis of Frequency Characteristic of Travelling-Wave Photodetector Using the FDTD Method (FDTD를 이용한 Travelling-Wave Photodetector의 주파수 특성 해석)

  • 공순철;이정훈;이승진;최영완
    • Proceedings of the Optical Society of Korea Conference
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    • pp.14-15
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    • 2000
  • We study the microwave characteristics of traveling-wave photodetector using the finite-difference time-domain method. We present two parameters for design, the width of PIN region and the thickness of i-layer, and analyze TWPD's property in frequency domain.

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6.25-Gb/s Optical Receiver Using A CMOS-Compatible Si Avalanche Photodetector

  • Kang, Hyo-Soon;Lee, Myung-Jae;Choi, Woo-Young
    • Journal of the Optical Society of Korea
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    • v.12 no.4
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    • pp.217-220
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    • 2008
  • An optical receiver using a CMOS-compatible avalanche photodetector (CMOS-APD) is demonstrated. The CMOS-APD is fabricated with $0.18{\mu}m$ standard CMOS technology and the optical receiver is implemented by using the CMOS-APD and a transimpedance amplifier on a board. The optical receiver can detect 6.25-Gb/s data with the help of the series inductive peaking effect.