Solid-state Imaging Device Research Articles

Principle study on exposure technique for double pulse high speed imaging based on direct control of CCD driving electrodes

Charge coupled device(CCD) is one kind of photoelectric solid-state imaging device with excellent performance. It has the features of large array and good image quality. Working under very complex driving timing, it usually has low frame frequency and can not meet the demand of high imaging frame rate. The method of equivalent high frame rate imaging technique is introduced based on normal CCD in this paper. Some CCDs can be drived via electrodes separately. To meet the imaging demands of high frame rate, high resolution and high quality of two frame imaging technique for pulse light images, the right kind of CCDs should be adopted. The most important is that the CCD electrodes must be controlled directly and respectively. The charge transfer period is a key point while designing CCD driving timing for separate pulse light integration, charge package transfer and readout for two pulse light images. The validation experiments for the principle of equivalent high frame rate exposure of two pulse light images has been accomplished. It is shown that two pulse light images with interval of about 2 μs can be distinguished while all CCD’s inherent excellent performance are retained. A kind of two framing camera system with simple structure can be developed based on this principle.

Isotopic effects on phonon anharmonicity in layered van der Waals crystals: Isotopically pure hexagonal boron nitride

Hexagonal boron nitride (h-BN) is a layered crystal that is attracting a great deal of attention as a promising material for nanophotonic applications. The strong optical anisotropy of this crystal is key to exploit polaritonic modes for manipulating light-matter interactions in 2D materials. h-BN has also great potential for solid-state neutron detection and neutron imaging devices, given the exceptionally high thermal neutron capture cross section of the boron-10 isotope. A good knowledge of phonons in layered crystals is essential for harnessing long-lived phonon-polariton modes for nanophotonic applications and may prove valuable for developing solid-state 10BN neutron detectors with improved device architectures and higher detection efficiencies. Although phonons in graphene and isoelectronic materials with a similar hexagonal layer structure have been studied, the effect of isotopic substitution on the phonons of such lamellar compounds has not been addressed yet. Here we present a Raman scattering study of the in-plane high-energy Raman active mode on isotopically enriched single-crystal h-BN. Phonon frequency and lifetime are measured in the 80–600-K temperature range for 10B-enriched, 11B-enriched, and natural composition high quality crystals. Their temperature dependence is explained in the light of perturbation theory calculations of the phonon self-energy. The effects of crystal anisotropy, isotopic disorder, and anharmonic phonon-decay channels are investigated in detail. The isotopic-induced changes in the phonon density of states are shown to enhance three-phonon anharmonic decay channels in 10B-enriched crystals, opening the possibility of isotope tuning of the anharmonic phonon decay processes.

Toward Scintillator High-Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI): Initial fabrication and characterization.

We present the first prototype Scintillator High-Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI). This detector includes a layer of avalanche amorphous Selenium (a-Se) (HARP) as the photoconductor in an indirect detector to amplify the signal and reduce the effects of electronic noise to obtain quantum noise-limited images for low-dose applications. It is the first time avalanche a-Se has been used in a solid-state imaging device and poses as a possible solution to eliminate the effects of electronic noise, which is crucial for low-dose imaging performance of AMFPI. We successfully deposited a solid-state HARP structure onto a 24 × 30 cm2 array of thin-film transistors (TFT array) with a pixel pitch of 85 μm. The HARP layer consists of 16 μm of a-Se with a hole-blocking and electron-blocking layer to prevent charge injection from the high-voltage bias and pixel electrodes, respectively. An electric field (ESe ) up to 105 V μm-1 was applied across the a-Se layer without breakdown. A 150 μm thick-structured CsI:Tl scintillator was used to form SHARP-AMFPI. The x-ray imaging performance is characterized using a 30 kVp Mo/Mo beam. We evaluate the spatial resolution, noise power, and detective quantum efficiency at zero frequency of the system with and without avalanche gain. The results are analyzed using cascaded linear system model (CLSM). An avalanche gain of 76 ± 5 was measured at ESe = 105 V μm-1 . We demonstrate that avalanche gain can amplify the signal to overcome electronic noise. As avalanche gain is increased, image quality improves for a constant (0.76 mR) exposure until electronic noise is overcome. Our system is currently limited by poor optical transparency of our high-voltage electrode and long integrating time which results in dark current noise. These two effects cause high-spatial frequency noise to dominate imaging performance. We demonstrate the feasibility of a solid-state HARP x-ray imager and have fabricated the largest active area HARP sensor to date. Procedures to reduce secondary quantum and dark noise are outlined. Future work will improve optical coupling and charge transport which will allow for frequency DQE and temporal metrics to be obtained.

Solid-State Terahertz Superresolution Imaging Device in 130-nm SiGe BiCMOS Technology

Breaking through diffraction limit at terahertz frequencies is currently performed with the near-field scanning optical microscopy, which suffers from low integration and sensitivity limitations. In this paper, a solid-state superresolution imaging device in 130-nm SiGe BiCMOS technology operating around 534-562 GHz is presented. The device exhibits a singlechip integration of the complete imaging functionality, including a tunable CW illumination source, near-field sensing, and power detection with a high response of up to 9.65 μA and a noise√ equivalent power of around 15-21 pW/ Hz at 60 kHz. Here, the stopband characteristics of a novel cross-bridged double splitring resonator are exploited as an object-tunable transmission gate between a 3-push Colpitts oscillator and a simple HBT power detector. The resonator features a 3-D topography to achieve high-spatial confinement of the surface near-fields and is capable of resolving structural details with an estimated lateral resolution down to 10-12 μm. For a separate antenna-coupled oscillator breakout, a radiated power of up to 28.2 μW was measured. Furthermore, a 2-D raster-scanned superresolution image with a remarkable signal-to-noise ratio of 42 dB was captured for the device operating even at dc.

Structural, electronic and photoluminescence properties of Eu3+-doped CaYAlO4 obtained by using citric acid complexes as precursors

The search for new materials that meet the current technological demands for photonic applications, make the Rare Earth ions embedded in inorganic oxides as excellent candidates for several technological devices. This work presents the synthesis of Eu3+-doped CaYAlO4 using citric acid as ligand to form a complex precursor. The methodology used has big draw due to its easy handling and low cost of the materials. The thermal analysis of viscous solutions was evaluated and the obtained compounds show the formation of a polycrystalline tetragonal phase. Rietveld refinement was used to understand the structural and the cell parameters of the crystalline phase as a function of temperature of heat-treatment. Crystallite size and microstrain were determined and were shown to have a direct relationship with the temperature of the heat-treatment. The band-gap of the CaYAlO4 doped with 1 and 10 mol% of Eu3+ showed values close to 4.30 eV, resulting in their transparency in the visible region between 330 and 750 nm. Besides the intense photoluminescence from Eu3+, a study was conducted to evaluate the possible position of the Eu3+ in the CaYAlO4 as host lattice. Lifetime of the emission decay from Eu3+ excited state 5D0 show that CaYAlO4 is a good host to rare earth ions, once it can avoid clustering of these ions in concentration as high as 10 mol%. The predictions of the sublevels of the 7F1 crystal field level are discussed through the method of equivalent nearest neighbours (MENN). The intensity parameters (Ωλ, λ = 2 and 4) are reproduced with physically reasonable values of average polarizabilities. The set of charge factors used in both calculations are in good agreement with the charge of the europium ion described by the Batista-Longo improved model (BLIM). The quantum efficiencies of the materials were calculated based on Judd-Ofelt theory. Based on the results obtained in this work, the materials have potential use in photonic devices such as lasers and solid state imaging devices in the red region of electromagnetic spectrum.

Investigation of structural, optical and morphological properties of copper doped zinc sulphide nanoparticles

Semiconductor nanoparticles doped with transition metal ions can influence the transition probabilities and electronic structure. The undoped and copper doped zinc sulphide nanoparticles with various concentrations are synthesized by wet chemical co-precipitation method. These nanoparticles are characterized by using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), UV–visible (UV–vis) absorption spectroscopy, Fourier Transform Infrared (FT-IR) Spectroscopy, conductivity measurement and time-resolved photoluminescence studies. X-ray powder diffraction analysis reveals that the synthesized samples have cubic zinc blende structure. The Scanning Electron Microscope shows the synthesized nanoparticles are agglomerated. The UV–visible spectra reveal the absorption edge is red shifted. The FT-IR spectra show vibrational peaks around 617cm−1 which indicate the presence of Cu–S stretching modes. The AC conductivity measurement confirms the semiconducting nature and shows a marked increase in conductivity as the doping concentration of copper increases. The photoluminescence shows that the emission at 426nm may be due to transition from the conduction band to the zinc vacancies. These transition metal ions doped semiconductor nanoparticles have important applications in solid state lighting, imaging, and other photonic devices.

Witnessing the Birth of VLSI Design

I have had several lucky breaks in my career. One of them was the opportunity to be immersed in the emergence of VLSI technology and its associated design methodology. I got my Ph.D. in Experimental Physics from the University of Basel, Switzerland, in 1969. My first job was with Bell Telephone Laboratories in Murray Hill, New Jersey. Because of my thesis, in which I studied the behavior of Interface States in Metal-Oxide-Semiconductor Field-Effect Transistors, I was placed into Lab 225, which was engaged in building solid state imaging devices based on the brand new CCD (Charge-Coupled Device) technology, which had been conceived there a few months earlier. When I arrived, the group with Mike Tompsett and Gil Amelio had just demonstrated a CCD sensor array with 8 by 8 pixels. Since I have been enamored with geometry ever since high-school, I jumped to the opportunity to design the layouts of much larger imaging arrays, first with 128 by 128 pixels, and eventually (in 1973) with two interlaced fields of 256 scan lines, which was compatible with the American broadcast TV format. The latter device was way larger than any other IC chips of that time: It had ¾ of a million MOS electrodes placed in a rectangle measuring ½ inch by 5/8 of an inch (Figure 1).

An Optimized Sensor for Geostationary Orbit Satellite Payload

This paper describes a project that the earth can be observed in the staring mode with the high resolution solid state imaging device in the geostationary orbit,analyzes the geometric relations when the sensor operates in the staring mode,and according to the current solid state imaging devices,gives two kind of sensor designs employing 5 000 by 5 000 elements CCD and 1 000 by 1 000 elements infrared FPA,similar to VHRR and GOES 9 in performance.The analysis results indicate that it is a very attractive project in the meteorological and ocean remote sensing to observe the earth in the staring mode in the geostationary orbit.

The invention and early history of the CCD

As the first practical solid state imaging device, the invention of the charge coupled device has profoundly affected image sensing technology. They are used in a wide range of applications both as area and linear imaging devices starting with the replacement of imaging tubes used in commercial TV cameras and cam-corders. The rapid rise of their use in digital cameras has initiated the demise of film photography and created vast new markets with great economic benefit for many. Other uses include a wide variety of scientific, surveillance, and scanning applications. The inception of the device at Bell Labs by W. S. Boyle and G. E. Smith, Bell Syst. Tech. J. 49, 587 (1970);G. F. Amelio, M. F. Tompsett, and G. E. Smith, Bell Syst. Tech. J. 49, 593 (1970); W. S. Boyle and G. E. Smith, U.S. patent 3,792,322 (12 February 1974) was strongly influenced by several unique factors existing both within Bell Labs and the current world state of technology. These factors and their relevance will be discussed along with the train of thought leading to the invention. Early experimental devices and their initial applications were vigorously pursued and will be described. Mention of current applications will be given.

Istoriya izobreteniya priborov s zaryadovoi svyaz'yu

As the first practical solid state imaging device, the invention of the Charge Coupled Device has profoundly affected image sensing technology. They are used in many applications both as area and linear imaging devices.

The invention and early history of the CCD

As the first practical solid-state imaging device, the invention of the Charge Coupled Device has profoundly affected image sensing technology. They are used in a wide range of applications as both area and linear imaging devices starting with the replacement of imaging tubes used in commercial TV cameras and camcorders. The rapid increase of their use in digital cameras has initiated the demise of film photography and created vast new markets with great economic benefit for many. Other uses include a wide variety of scientific, surveillance and scanning applications. The inception of the device at Bell Labs by Willard S. Boyle and George E. Smith in 1969 was strongly influenced by several unique factors existing both within Bell Labs and the current world state of technology. These factors and their relevance will be discussed along with the train of thought leading to the invention. Early experimental devices and their initial applications were vigorously pursued and will be described. Current applications will be mentioned.

Synthesis, Structural, and Optical Properties of Stable ZnS:Cu,Cl Nanocrystals

Stable water-suspendable Cu+-doped ZnS nanocrystals (NCs) have been synthesized with mercaptopropionic acid (MPA) as a capping molecule. The nanocrystals have been characterized using a combination of experimental techniques including UV-vis and photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma (ICP), and extended X-ray absorption fine structure (EXAFS). The UV-vis electronic absorption spectrum shows an excitonic peak at 310 nm, characteristic of quantum-confined ZnS NCs. This excitonic peak does not change noticeably with Cu+ doping. XRD confirms the formation of ZnS nanocrystals, and the average size of the NCs has been determined to be around 6 nm by TEM. The incorporation of Cu+ into the ZnS is manifested as a substantial red-shift of the emission band in the PL spectra upon addition of Cu2+ that was reduced into Cu+ during the synthesis reaction. EXAFS data were obtained to confirm copper doping as well as determine the local structure about Cu+ and Zn2+ in the NCs. Fitting to the EXAFS data for Cu+ suggests that most Cu+ ions are located near the surface within the ZnS NCs and that a significant fraction may be in the form of CuS as found in bulk material. These combined optical and structural studies have provided important new insight into the relevant electronic energy levels and their correlation to the optical and structural properties of ZnS:Cu,Cl NCs. This has important implications in potential applications of this phosphor material for solid state lighting, imaging, and other photonic devices.

CMOS monolithic active pixel sensors (MAPS) for scientific applications: Some notes about radiation hardness

Invented in the early 1990s on both sides of the Atlantic, Monolithic Active Pixel Sensors (MAPS) in a CMOS technology are today the most sold solid-state imaging device, overtaking the traditional technology of Charge-Coupled Devices (CCD). The slow uptake of CMOS MAPS started from low-end applications, like for example web cams and is slowly pervading the high-end applications, like for example in prosumer digital cameras. Higher specifications are required for scientific applications: very low noise, high speed, high dynamic range, large format and radiation hardness are some of these requirements. This paper will briefly review the main results on radiation hardness for monolithic active pixel sensors.

CMOS Monolithic Active Pixel Sensors (MAPS): Developments and future outlook

Re-invented in the early 1990s, on both sides of the Atlantic, Monolithic Active Pixel Sensors (MAPS) in a CMOS technology are today the most sold solid-state imaging devices, overtaking the traditional technology of Charge-Coupled Devices (CCD). The slow uptake of CMOS MAPS started with low-end applications, for example web-cams, and is slowly pervading the high-end applications, for example in prosumer digital cameras. Higher specifications are required for scientific applications: very low noise, high speed, high dynamic range, large format and radiation hardness are some of these requirements. This paper will present a brief overview of the CMOS Image Sensor technology and of the requirements for scientific applications. As an example, a sensor for X-ray imaging will be presented. This sensor was developed within a European FP6 Consortium, intelligent imaging sensors (I-ImaS).

Photo-Current Multiplication Phenomenon of Amorphous Silicon-Based Multilayer Photodiodes Fabricated on Crystalline Silicon Substrate

Recently, high-resolution and high-density solid-state imaging devices have been in high demand due to their high photogain because the smaller pixel size makes the smaller photo-current dependent on the reduced area. Multilayer photodiodes having a-SiC:H/a-Si:H/a-SiN:H structures fabricated on the crystalline silicon (c-Si) substrate were studied for their photo-multiplication effects which marked a gain of 6.6. These multiplication phenomenona arose in the wavelength region longer than 550 nm, while in the shorter-wavelength region, the photogain was less than unity. This is explained by the electron carrier process where the carriers photogenerated in the c-Si substrate are accumulated at the a-SiN:H/c-Si interface and tunneled via localized states in the a-SiN:H layer by the induced high electric field. From these results, it is considerably difficult to support the theory of avalanche effect to explain these photo-multiplication effects.

Analysis of signal to noise ratio of photoconductive layered solid-state imaging device

The signal to noise ratio of the photoconductive layered solid-state imaging device (PSID) has been theoretically derived. In this analysis the noise suppression effect due to residual signal electrons in the storage diode after read-out operation, the optical shot noise, and the fluctuation of the number of transferred signal electrons due to incomplete readout signal electrons were considered. The obtained result showed good agreement to the experimental result.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Radiation effects on solid state imaging devices

Radiation effects on semiconductor imaging arrays are reviewed, with special emphasis on the performance of silicon CCDs in space—though other environments and detector materials are also considered. The basic phenomena of permanent ionization damage, bulk displacement damage and transient charge production are examined as well as methods for predicting mission performance from ground test data. Approaches for device hardening are also discussed.

Photodegradation for a hydrogenated amorphous silicon photoconversion layer in a solid-state image sensor

Photodegradation for a hydrogenated amorphous silicon photoconversion layer in a two-level solid-state imaging device was studied. The residual current after a light pulse, which causes image lag for the imaging device, was most sensitive to light exposure among several properties, so that the residual current determines the lifetime for the photoconversion layer. The space charge was also increased with increasing residual current by light exposure, because both properties reflected light-induced defect states. The space charge was found to be a good monitor for the photodegradation. The space-charge density had light intensity and exposure-time dependency, which is similar to that for dangling bond density. The lifetime for the photoconversion layer, which was evaluated through the space-charge density change, was 1.5*10/sup 7/ h under standard illumination for the imager. This lifetime is sufficiently long for practical imager use.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A 250 k-pixel SIT image sensor operating in its high-sensitivity mode

A solid-state imaging device which uses a static induction transistor (SIT) is examined. The image sensor consists of 530(H)*490(V) pixels and is suitable for a 2/3-in optical format. An analysis of its operation predicts that the performance of the image sensor can be examined in detail using an equivalent circuit. A noise equivalent irradiance of 1.5*10/sup -4/ mu W/cm/sup 2/, when using light-emitting diodes ( lambda =660 nm) as a light source, was obtained in a frame integration mode. This is comparable to that of a high-sensitivity silicon intensifier target tube, although a large image lag of 80% during the third frame is also present. High sensitivity, is achieved because the gate reset levels of the SIT depend on the exposure and the change of the gate reset levels added to the output signal. It is predicted that the image sensor will be highly sensitive but that it will have a large image lag. >

A New High-Speed Camera System for Broadcast Use — The Action Analyzer

A new high-speed color video camera for broadcast use provides high-quality slow-motion images, which previously had to be taken by a film camera. The system is made possible by a new solid-state imaging device, which has 250,000 pixels and an electronic shutter. It can take 360 field pictures/sec. An 800-Mbyte solid-state storage permits the recording of real-time events for up to 12 sec in a loop, thus allowing an operator to replay at any speed immediately following recording by slow motion.