A 140 dB Single-Exposure Dynamic-Range CMOS Image Sensor with In-Pixel DRAM Capacitor

Oh, Youngsun; Jungwook, Lim; Park, Soeun; Yoo, Dongsuk; Lim, Moosup; Park, Joongseok; Kim, Seojoo; Jung, Minwook; Kim, Sungkwan; Lee, Junetaeg; Baek, In-Gyu; Ryu, Kwangyul; Kim, Kyungmin; Jang, Youngtae; Keel, Min-Sun; Bae, Gyu-Jin; Yoo, Seunghun; Jeong, Youngkyun; Kim, Bum Suk; Ahn, Jin-Hyun; Lee, Haechang; Yim, JoonSeo

doi:10.1109/iedm45625.2022.10019558

Cited by 4 publications

(5 citation statements)

References 6 publications

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“…Pixels with higher FWC density per unit area can be found from the literature; however, most of them have adopted additional capacitors such as the lateral overflow integration trench capacitor [22], deep trench isolation with hole collection [23]. DRAM capacitor [40], Metal-Insulator-Metal capacitor [41], or 3-dimensional capacitor [42]. Assuming low readout noise as presented in our previous report [11], with the high FWC presented in this work, a high linear dynamic range over 100 dB is estimated, while the 3 T pixel shows 82 dB, presenting a significant increase in the dynamic range by the introduction of the novel pixel architecture [11,21].…”

Section: Discussionmentioning

confidence: 99%

A Thin-Film Pinned-Photodiode Imager Pixel with Fully Monolithic Fabrication and beyond 1Me- Full Well Capacity

Kim,

Berghmans,

Siddik

et al. 2023

Sensors

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Thin-film photodiodes (TFPD) monolithically integrated on the Si Read-Out Integrated Circuitry (ROIC) are promising imaging platforms when beyond-silicon optoelectronic properties are required. Although TFPD device performance has improved significantly, the pixel development has been limited in terms of noise characteristics compared to the Si-based image sensors. Here, a thin-film-based pinned photodiode (TF-PPD) structure is presented, showing reduced kTC noise and dark current, accompanied with a high conversion gain (CG). Indium-gallium-zinc oxide (IGZO) thin-film transistors and quantum dot photodiodes are integrated sequentially on the Si ROIC in a fully monolithic scheme with the introduction of photogate (PG) to achieve PPD operation. This PG brings not only a low noise performance, but also a high full well capacity (FWC) coming from the large capacitance of its metal-oxide-semiconductor (MOS). Hence, the FWC of the pixel is boosted up to 1.37 Me- with a 5 μm pixel pitch, which is 8.3 times larger than the FWC that the TFPD junction capacitor can store. This large FWC, along with the inherent low noise characteristics of the TF-PPD, leads to the three-digit dynamic range (DR) of 100.2 dB. Unlike a Si-based PG pixel, dark current contribution from the depleted semiconductor interfaces is limited, thanks to the wide energy band gap of the IGZO channel material used in this work. We expect that this novel 4 T pixel architecture can accelerate the deployment of monolithic TFPD imaging technology, as it has worked for CMOS Image sensors (CIS).

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Section: Discussionmentioning

confidence: 99%

A Thin-Film Pinned-Photodiode Imager Pixel with Fully Monolithic Fabrication and beyond 1Me- Full Well Capacity

Kim,

Berghmans,

Siddik

et al. 2023

Sensors

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“…Third, to achieve better DC, creating doping gradient on P-epi [24] is beneficial to increasing charge collection efficiency in the vertical direction, resulting in better depth precision. Lastly, the RN can be reduced by implementing a column-ADC circuit and using higher density in-pixel memory with textured deep trench SiN capacitors [29] or high-capacity DRAM capacitors [30], [31]. Moreover, by utilizing high-density capacitor and 3-D stacking techniques, it is possible to implement more in-pixel memory, which can extend the duration of burst imaging even at a higher frame rate.…”

Section: B Hs Modementioning

confidence: 99%

A 134×132 4-Tap CMOS Indirect Time-of-Flight Range Imager Using In-Pixel Memory Array With 10 Kfps High-Speed Mode and High Precision Mode

Kuo

Kuroda

2024

IEEE J. Solid-State Circuits

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“…When the SPD-CDS readout (gray dashed line) is implemented, the second SNR dip is greatly improved up to 25 dB at 105 • C, as shown in Figure 5a. The SNR dip can be further improved by increasing the FWC of LPD to improve SNR or reducing the RN noise of SPD-CDS by introducing a high conversion gain of the SPD-CDS mode [7]. When LOFIC operates, a third SNR dip becomes rather prominent and is determined by a noise floor of the incomplete CDS of SPD-LOF.…”

Section: Dr(db) = 20 × Logmentioning

confidence: 99%

“…However, as the pixel size gradually shrinks, this sub-pixel architecture not only faces a critical limit where the DR is no longer expanded due to the restricted pixel area for the in-pixel capacitor, but also noticeably deteriorates SNR during HDR image synthesis. The high-density inpixel capacitor approach could overcome the former restriction and the technology is still evolving through a variety of the high capacity capacitors [5,7]. However, such scaling inherently creates SNR degradation as a result of the small full-well capacity (FWC) of the PDs.…”

Section: Introductionmentioning

confidence: 99%

Automotive 2.1 μm Full-Depth Deep Trench Isolation CMOS Image Sensor with a 120 dB Single-Exposure Dynamic Range

Yoo,

Jang,

Kim

et al. 2023

Sensors

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An automotive 2.1 μm CMOS image sensor has been developed with a full-depth deep trench isolation and an advanced readout circuit technology. To achieve a high dynamic range, we employ a sub-pixel structure featuring a high conversion gain of a large photodiode and a lateral overflow of a small photodiode connected to an in-pixel storage capacitor. With the sensitivity ratio of 10, the expanded dynamic range could reach 120 dB at 85 °C by realizing a low random noise of 0.83 e- and a high overflow capacity of 210 ke-. An over 25 dB signal-to-noise ratio is achieved during HDR image synthesis by increasing the full-well capacity of the small photodiode up to 10,000 e- and suppressing the floating diffusion leakage current at 105 °C.

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A 140 dB Single-Exposure Dynamic-Range CMOS Image Sensor with In-Pixel DRAM Capacitor

Cited by 4 publications

References 6 publications

A Thin-Film Pinned-Photodiode Imager Pixel with Fully Monolithic Fabrication and beyond 1Me- Full Well Capacity

A Thin-Film Pinned-Photodiode Imager Pixel with Fully Monolithic Fabrication and beyond 1Me- Full Well Capacity

A 134×132 4-Tap CMOS Indirect Time-of-Flight Range Imager Using In-Pixel Memory Array With 10 Kfps High-Speed Mode and High Precision Mode

Automotive 2.1 μm Full-Depth Deep Trench Isolation CMOS Image Sensor with a 120 dB Single-Exposure Dynamic Range

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