Optimization of Pinned Photodiode Pixels for High-Speed Time of Flight Applications

Acerbi, Fabio; Moreno-García, Manuel; Köklü, Gözen; Gancarz, Radoslaw Marcin; Büttgen, Bernhard; Biber, Alice; Furrer, Daniel; Stoppa, David

doi:10.1109/jeds.2018.2807918

Cited by 23 publications

(9 citation statements)

References 8 publications

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“…The latter is shown in Fig. 6(a)-(d) for different values of V TG : 2.0, 1.5, 1.0, and 0.5 V. The simulation results obtained during the charge transfer can be compared with (10). The agreement between TCAD simulation results and the proposed model is good and confirms that the derived expression predicts the characteristic of the charge transfer from the PPD to the SN.…”

Section: A Charge Transfer Across a Potential Barriersupporting

confidence: 59%

“…Since in a p + np PPD, the electrons are transferred to the SN, the VCCS indicates a current flowing from the SN to the PPD. Relying on the proposed model, the transfer current is expressed as a function of V TG and V PPD according to (10). This equivalent circuit, together with the proposed expressions, represents an essential step toward the circuit-level design of PPD-based pixels in CISs.…”

Section: B Model Implementation and Equivalent Circuit Of Ppdmentioning

confidence: 99%

“…The PPD is usually associated with a transfer gate (TG), which transfers the electrons accumulated during illumination within the photodiode to the sense node (SN), having lower capacitance and hence providing a readable voltage variation. The PPD/TG interface is becoming more critical for further improvements [5] in advanced applications, e.g., subelectron read noise levels [6], [7], high frame rates [8], [9], and time of flight (ToF) [10], [11]. Moreover, the nonideal effects due to the charge transfer mechanism from the PPD to the SN, which affects both the static and dynamic operations, has recently become a new research topic [12]- [14].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Compact Modeling of Charge Transfer in Pinned Photodiodes for CMOS Image Sensors

Capoccia

Boukhayma

Jazaeri

et al. 2019

IEEE Trans. Electron Devices

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In this paper, we propose a physics-based compact model of the pinned photodiode (PPD) combined with the transfer gate. A set of analytical expressions is derived for the 2-D electrostatic profile, the PPD capacitance, and the charge transfer current. The proposed model relies on the thermionic emission current mechanism, the barrier modulation, and the full-depletion approximation to obtain the charge transfer current. The proposed physics-based model is fully validated with technology computer-aided design simulations, i.e., stationary and optoelectrical simulations. The development of such a compact model for PPD represents an essential step toward the design, simulation, and optimization of PPD-based pixels in CMOS image sensors. Index Terms-Charge transfer, CMOS image sensors (CISs), compact modeling, pinned photodiode (PPD).

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Section: A Charge Transfer Across a Potential Barriersupporting

confidence: 59%

Section: B Model Implementation and Equivalent Circuit Of Ppdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Compact Modeling of Charge Transfer in Pinned Photodiodes for CMOS Image Sensors

Capoccia

Boukhayma

Jazaeri

et al. 2019

IEEE Trans. Electron Devices

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“…The other one is to optimize the potential profile of n-well in PPD. [3], [4], [6], [7] achieve this by adjusting the shape of the pixels. [8], [9] introduce the effect of the pinning potential of PPD.…”

Section: Introductionmentioning

confidence: 99%

Analyses of Pinned Photodiodes With High Resistivity Epitaxial Layer for Indirect Time-of-Flight Applications

Fang

Yang

et al. 2020

IEEE Access

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This paper analyzes the performance of pinned photodiode (PPD) for Time-of-Flight(ToF) applications on high resistivity epitaxial wafers. Due to its wide depletion region, high epitaxial resistivity PPDs feature some key advantages in collecting photogenerated charges. This paper compares the demodulation contrast of the same pixel design on epitaxial wafers with different resistivity at near-infrared wavelength to analyze their performance. By comparing the simulated profile of pixels with different epitaxial resistivity, the characteristics of the PPD pixel on high resistivity epitaxial wafer when collecting photogenerated charges are concluded. This paper also discusses the effects of using high resistivity epitaxial wafer with various design parameters. It is found that the use of high resistivity epitaxial wafer can greatly improve crosstalk performance, allow pixels to work at higher modulation frequencies, and enable largesized pixels to have good demodulation capabilities. INDEX TERMSPinned photodiode, time-of-flight, ToF, high resistivity, CMOS image sensor.

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“…Input-referred total noise for Pixel A (a) and Pixel B (b) as a function of the CMS order M. The measurements are compared with the total noise expression proposed in(5).…”

mentioning

confidence: 99%

Experimental Verification of the Impact of Analog CMS on CIS Readout Noise

Capoccia

Boukhayma

Enz

2020

IEEE Trans. Circuits Syst. I

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In this article, the impact of the combination of the column-level gain and the correlated multiple sampling (CMS) on the noise of CMOS image sensor (CIS) readout chains is first analyzed. The theory is then validated experimentally with CIS readout chains embedding two different pixels, a variable gain column-level amplifier (CLA) and a passive switched-capacitor (SC) CMS circuit. The noise measurements include photon transfer curves (PTCs) for different gains and pixels and they show reasonably well that CMS reduces the 1/f noise by about 33% for order 8 as expected theoretically.

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Optimization of Pinned Photodiode Pixels for High-Speed Time of Flight Applications

Cited by 23 publications

References 8 publications

Compact Modeling of Charge Transfer in Pinned Photodiodes for CMOS Image Sensors

Compact Modeling of Charge Transfer in Pinned Photodiodes for CMOS Image Sensors

Analyses of Pinned Photodiodes With High Resistivity Epitaxial Layer for Indirect Time-of-Flight Applications

Experimental Verification of the Impact of Analog CMS on CIS Readout Noise

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