New mechanism of plasma induced damage on CMOS image sensor: Analysis and process optimization

Carrere, J.-P.; Oddou, JP; Richard, C.; Jenny, C.; Gatefait, Maxime; Place, S.; Aumont, C.; Tournier, Arnaud; Roy, F.

doi:10.1109/essderc.2010.5617725

Cited by 7 publications

(5 citation statements)

References 14 publications

(11 reference statements)

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“…to an increase of the electrostatic potential in the semiconductor). This conclusion is in good agreement with the positive charge trapping observed in CIS PMD nitride-oxide films exposed to plasma induced radiation [32].…”

Section: A Degradation Mechanismssupporting

confidence: 90%

“…Radiation hardening by process is also possible but it has a cost. An increase of the pinning layer doping concentration would most likely delay the radiation effects discussed here (as discussed in [32], [34]) but extreme care should be taken since increasing the pinning doping concentration could result in severe CTE loss or to significant electric field enhancement of the dark current. The use of rad-hard oxide for the PMD and spacer formation would improve much the radiation hardness of the CIS but it represents an important process modification that may be difficult to get.…”

Section: B Radiation-hardening Perspectivesmentioning

confidence: 99%

“…15. Composite nitride-oxide films are known to trap electrons as well as holes [28], [29] when exposed to ionizing radiation contrary to silicon dioxide that mainly trap holes [30] (as does the PMD [31] despite the fact it is itself constituted by some nitride [32]). The resulting apparent charge in the silicon depends on the different thicknesses (and natures) of the oxide and nitride that constitute the film [28], [29].…”

Section: A Degradation Mechanismsmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Transfer Gate Design and Bias on the Radiation Hardness of Pinned Photodiode CMOS Image Sensors

Goiffon

Estribeau

Cervantes

et al. 2014

IEEE Trans. Nucl. Sci.

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The effects of Cobalt 60 gamma-ray irradiation on pinned photodiode (PPD) CMOS image sensors (CIS) are investigated by comparing the total ionizing dose (TID) response of several transfer gate (TG) and PPD designs manufactured using a 180 nm CIS process. The TID induced variations of charge transfer efficiency (CTE), pinning voltage, equilibrium full well capacity (EFWC), full well capacity (FWC) and dark current measured on the different pixel designs lead to the conclusion that only three degradation sources are responsible for all the observed radiation effects: the pre-metal dielectric (PMD) positive trapped charge, the TG sidewall spacer positive trapped charge and, with less influence, the TG channel shallow trench isolation (STI) trapped charge. The different FWC evolutions with TID presented here are in very good agreement with a recently proposed analytical model. This work also demonstrates that the peripheral STI is not responsible for the observed degradations and thus that the enclosed layout TG design does not improve the radiation hardness of PPD CIS. The results of this study also lead to the conclusion that the TG OFF voltage bias during irradiation has no influence on the radiation effects. Alternative design and process solutions to improve the radiation hardness of PPD CIS are discussed.

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Section: A Degradation Mechanismssupporting

confidence: 90%

Section: B Radiation-hardening Perspectivesmentioning

confidence: 99%

Section: A Degradation Mechanismsmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Transfer Gate Design and Bias on the Radiation Hardness of Pinned Photodiode CMOS Image Sensors

Goiffon

Estribeau

Cervantes

et al. 2014

IEEE Trans. Nucl. Sci.

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“…1). There are two possible mechanisms that can explain this observation: 1) The radiation induced trapped charge density becomes large enough to change the electrostatic potential distribution above the pinned photodiode (by reducing the effective doping concentration of the P+ pinning layer), leading to the extension of the PPD depletion to the top oxide interface (as explained in [17]).…”

Section: B Evolution With Irradiationmentioning

confidence: 99%

Identification of radiation induced dark current sources in Pinned PhotoDiode CMOS Image Sensors

Goiffon¹,

Virmontois²,

Magnan³

et al. 2011

2011 12th European Conference on Radiation and Its Effects on Components and Systems

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This paper presents an investigation of Total Ionizing Dose induced dark current sources in Pinned PhotoDiodes (PPD) CMOS Image Sensors based on pixel design variations. The influence of several layout parameters is studied. Only one parameter is changed at a time enabling the direct evaluation of its contribution to the observed device degradation. By this approach, the origin of radiation induced dark current in PPD is localized on the pixel layout. The PPD peripheral STI does not seem to play a role in the degradation. The PPD area and an additional contribution independent on the pixel dimensions appear to be the main sources of the TID induced dark current increase.

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“…The dark noise of CMOS image sensors can be affected by plasma process steps, either by purely electrical stress [1] or by the combination of ultraviolet (UV) photon interaction and electrical stress [2]. This dark noise degradation is caused by an increase of the dark current non-uniformity into the pixel matrix, or a temporal noise degradation of the pixel MOS.…”

Section: Introductionmentioning

confidence: 99%

CMOS Image Sensors and Plasma Processes: How PMD Nitride Charging Acts on the Dark Current

Sacchettini

Carrere

Duru

et al. 2019

Sensors

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Plasma processes are known to be prone to inducing damage by charging effects. For CMOS image sensors, this can lead to dark current degradation both in value and uniformity. An in-depth analysis, motivated by the different degrading behavior of two different plasma processes, has been performed in order to determine the degradation mechanisms associated with one plasma process. It is based on in situ plasma-induced charge characterization techniques for various dielectric stack structures (dielectric nature and stack configuration). A degradation mechanism is proposed, highlighting the role of ultraviolet (UV) light from the plasma in creating an electron hole which induces positive charges in the nitride layer at the wafer center, and negative ones at the edge. The trapped charges de-passivate the SiO2/Si interface by inducing a depleted interface above the photodiode, thus emphasizing the generation of dark current. A good correlation between the spatial distribution of the total charges and the value of dark current has been observed.

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New mechanism of plasma induced damage on CMOS image sensor: Analysis and process optimization

Cited by 7 publications

References 14 publications

Influence of Transfer Gate Design and Bias on the Radiation Hardness of Pinned Photodiode CMOS Image Sensors

Influence of Transfer Gate Design and Bias on the Radiation Hardness of Pinned Photodiode CMOS Image Sensors

Identification of radiation induced dark current sources in Pinned PhotoDiode CMOS Image Sensors

CMOS Image Sensors and Plasma Processes: How PMD Nitride Charging Acts on the Dark Current

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