Analysis and Optimization of Noise Response for Low-Noise CMOS Image Sensors

CMOS image sensors are nowadays widely used in imaging applications and particularly in low light flux applications. This is really possible thanks to a reduction of noise obtained, among others, by the use of pinned photodiode associated with a Correlated Double Sampling readout. It reveals new noise sources which become the major contributors. This paper presents noise measurements on low-noise CMOS image sensor. Image sensor noise is analyzed and optimization is done in order to reach an input referred noise of 1 electron rms by column gain amplifier insertion and dark current noise optimization. Pixel array noise histograms are analyzed to determine noise impact of dark current and column gain amplifier insertion. Transfer noise impact, due to the use of pinned photodiode (4T photodiode), is also measured and analyzed by a specific readout sequence

Deterministic Sub-wavelength Control of Light Confinement in Nanostructures

We propose a novel deterministic protocol, based on continuous light flows, that enables us to control the concentration of light in generic plasmonic nanostructures. Based on an exact inversion of the response tensor of the nanosystem, the so-called Deterministic Optical Inversion (DOPTI) protocol provides a physical solution for the incident field leading to a desired near field pattern, expressed in the form of a coherent superposition of high order beams. We demonstrate the high degree of control achieved on complex plasmonic architectures and quantify its efficiency and accuracy

Radiation Effects in Pinned Photodiode CMOS Image Sensors: Pixel Performance Degradation Due to Total Ionizing Dose

Several Pinned Photodiode (PPD) CMOS Image Sensors (CIS) are designed, manufactured, characterized and exposed biased to ionizing radiation up to 10 kGy(SiO2 ). In addition to the usually reported dark current increase and quantum efficiency drop at short wavelengths, several original radiation effects are shown: an increase of the pinning voltage, a decrease of the buried photodiode full well capacity, a large change in charge transfer efficiency, the creation of a large number of Total Ionizing Dose (TID) induced Dark Current Random Telegraph Signal (DC-RTS) centers active in the photodiode (even when the Transfer Gate (TG) is accumulated) and the complete depletion of the Pre-Metal Dielectric (PMD) interface at the highest TID leading to a large dark current and the loss of control of the TG on the dark current. The proposed mechanisms at the origin of these degradations are discussed. It is also demonstrated that biasing (i.e., operating) the PPD CIS during irradiation does not enhance the degradations compared to sensors grounded during irradiation

Smart CMOS image sensor for lightning detection and imaging

We present a CMOS image sensor dedicated to lightning detection and imaging. The detector has been designed to evaluate the potentiality of an on-chip lightning detection solution based on a smart sensor. This evaluation is performed in the frame of the predevelopment phase of the lightning detector that will be implemented in the Meteosat Third Generation Imager satellite for the European Space Agency. The lightning detection process is performed by a smart detector combining an in-pixel frame-to-frame difference comparison with an adjustable threshold and on-chip digital processing allowing an efficient localization of a faint lightning pulse on the entire large format array at a frequency of 1 kHz. A CMOS prototype sensor with a 256×256 pixel array and a 60 μm pixel pitch has been fabricated using a 0.35 μm 2P 5M technology and tested to validate the selected detection approach

Study of CCD Transport on CMOS Imaging Technology: Comparison Between SCCD and BCCD, and Ramp Effect on the CTI

This paper presents measurements performed on Charge Coupled Device (CCD) structures manufactured on a deep submicron CMOS imaging technology, in surface channel CCD and in buried channel CCD mode. The charge transfer inefficiency is evaluated for both CCD modes with regard to the injected charge, and the influence of the rising and falling time effect is explored. Controlling the ramp and especially reducing its abruptness allows to get much lower CTI in BCCD mode. In contrary, we did not observe any effect of the ramp on SCCD mode, due to the presence of interface traps at the silicon – oxide interface

Design Impact on Charge Transfer Inefficiency of Surface CCD on CMOS Devices: TCAD and Characterization Study

This work presents a study of design optimization of CCD on CMOS devices, in order to minimize the Charge Transfer Inefficiency (CTI). To achieve this goal, 3D Technology Computer Aided Design (TCAD) simulations with a trap model at silicon–oxide interface were conducted, and measurements on two test chips manufactured on two different foundries were performed. TCAD simulations predict trends in agreement with measurements, but trap models at STI and gate oxides should be adapted accordingly to the technology used. Some design variations show results depending on the technology chosen, and the best CTI reduction is obtained with an increase of Pwell inclusion over STI edges

Contourite distribution and bottom currents in the NW Mediterranean Sea: Coupling seafloor geomorphology and hydrodynamic modelling

Contourites are common morphological features along continental margins where currents encounter the seafloor. They can provide long-term archives of palaeoceanography, may be prone to sediment instability, and can have a great potential for hydrocarbon exploration. Despite their importance and increasingly recognised ubiquitous occurrence worldwide, the link between oceanographic processes and contourite features is poorly constrained. In particular, it is unclear under which specific conditions sediments are mobilised, modified and deposited by bottom currents. Here, we aim to determine key bottom current characteristics (velocity and bottom shear stress) affecting contourite deposition, by assuming that recent oceanographic regimes may be extended back in time over the past glacial-interglacial cycles, with strong winter circulation assumed similar to glacial conditions and weak summer circulation to interglacials. We present an integrated study from the NW Mediterranean Sea that couples results of the MARS3D hydrodynamic model with high-resolution sedimentological and geophysical data (piston cores, multibeam bathymetry and high resolution seismic data). Near bottom circulation was modelled during winter and summer 2013 as representative of past periods of high and low current intensity, respectively. Model results match well with the extent of contourite depositional systems and their different localised morphologic elements. We deduce that higher intensity events control the formation of erosional features such as moats and abraded surfaces. The heterogeneous distribution of bottom-current intensity on slopes explains the development of different types of contourite drifts. Plastered drifts form in zones of low bottom-current velocities constrained upslope and downslope by higher current velocities. Separated elongated mounded drifts develop where fast bottom-currents decelerate at foot of the slope. In contrast, no mounded contourite morphologies develop when the current velocity is homogeneous across the slope, especially in margins prone to downslope sediment transport processes. In confined basins, gyres may transport sediment in suspension from a margin with a high sediment supply to an adjacent starved margin, favouring the development of fine-grained contourites in the latter. Our results provide new insights into how detailed bottom-circulation modelling and seafloor geomorphological analyses can improve the understanding of palaeoflow-regimes, at least over time spans when the overall paleogeography and the distribution of contourite drifts is comparable to present-day conditions. The approach of coupled hydrodynamic models and geomorphological interpretations proposed here for depositional, erosional and mixed contourite features may be used to understand other areas affected by bottom currents, and for a better conceptual understanding of bottom-current processes and their interactions with the seafloor

Radiation Effects in CCD on CMOS Devices: First Analysis of TID and DDD Effects

As CMOS image sensors become more and more attractive and with high performances, it becomes possible to use CCD on CMOS devices with reasonable lengths. However, no study has been done on the radiation hardness of such CCD on CMOS devices. Therefore, we propose in this paper a first study of Charge Transfer Inefficiency (CTI) and dark current degradation under TID and DDD irradiations. To do so, test chips have been processed in conventional deep submicron CMOS imaging technologies, and characterized before and after irradiations

Marches bipède et quadrupède du babouin olive (Papio anubis) : activité musculaire comparée et perspectives évolutives

La marche bipède humaine est particulièrement raffinée et efficace. Les primates non-humains (PNHs), quant à eux, utilisent la bipédie occasionnellement au sein d’un répertoire posturo-locomoteur souvent varié. Dans le contexte de l’évolution des modes locomoteurs chez les primates (incluant les hominines), une hypothèse suggère l’existence d’un mécanisme de contrôle basique et similaire en bipédie et en quadrupédie. La tester nécessite une observation directe de l’activité musculaire liée à ..

Dark Current Spectroscopy in neutron, proton and ion irradiated CMOS Image Sensors: from Point Defects to Clusters

The dark current spectroscopy is tested on twenty CMOS image sensors irradiated with protons, neutrons and various ions at different energies. The aim of this work is to differentiate the effect of coulomb and nuclear interactions on the radiation-induced dark current distribution and to identify the main radiation-induced defects responsible for the dark current increase for each type of interaction. For low-energy protons and low-energy light ions (which produce well-separated low energy coulomb interactions), we find that most of the pixels belong to a quantized dark current spectrum at low dark current. In these pixels, the dark current increase seems mainly dominated by specific point defects such as the divacancy and the vacancy-phosphorus complex. Thus, these simple defects seem to form when the displacement damage is rather low and sparse. On the contrary, for nuclear interactions (with neutrons or high-energy protons) producing high coulomb NIEL silicon PKAs or for low energy heavy ions (also having high coulomb NIEL), the DCS spectrum is not visible and all the pixels belong to an exponential hot pixel tail which extends to very high dark current. In these pixels, the dark current increase is mainly dominated by defects with close-to-midgap energy levels. These defects seem more complex than point defects because they can have many different generation rates (explaining the smooth hot pixel tail) and because they tend to form when the displacement damage is high and dense