Charge coupled 8‐bit shift register
TL;DR: In this article, an 8-bit shift register based on the charge-coupled device concept was developed, which is essentially that of a linear array of 26 closely spaced MOS capacitors with a p-n junction at either end.
Abstract: An 8‐bit shift register has been developed based on the charge‐coupled device concept. The device configuration is essentially that of a linear array of 26 closely spaced MOS capacitors with a p‐n junction at either end. A packet of charge is inserted into the first capacitor from one of the p‐n junctions and then transferred down the array in a potential well created by sequential pulsing of the electrode potentials. A high‐charge transfer efficiency of greater than 99.9% per electrode has been obtained in this device for transfer times of 2μ sec. The use of the device as an 8‐bit shift register and a line imaging device are demonstrated thereby further verifying the charge‐coupled device concept and showing the basic feasibility of developing charge‐coupled devices for shift registers, logic operations, and optical imaging applications.
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TL;DR: In this paper, the development, physics, and technology of the pinned photodiode is reviewed and a detailed review of its use in CCD and CMOS image sensors is presented.
Abstract: The pinned photodiode is the primary photodetector structure used in most CCD and CMOS image sensors. This paper reviews the development, physics, and technology of the pinned photodiode.
364 citations
Cites methods from "Charge coupled 8‐bit shift register..."
...) The CCD was invented in 1969 at Bell Labs by Boyle and Smith [8] and its application to image sensors was immediately apparent and first reported by Tompsett, Amelio and Smith in 1970 [9]....
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Journal Article•
TL;DR: In this paper, the free charge transfer characteristics of charge-coupled devices (CCD's) are analyzed in terms of the charge motion due to thermal diffusion, self-induced drift, and fringing field drift.
Abstract: The free charge-transfer characteristics of charge-coupled devices (CCD's) are analyzed in terms of the charge motion due to thermal diffusion, self-induced drift, and fringing field drift. The charge-coupled structures considered have separations between the gates equal to the thickness of the channel oxide. The effect of each of the above mechanisms on charge transfer is first considered separately, and a new method is presented for the calculation of the self-induced field. Then the results of a computer simulation of the charge-transfer process that simultaneously considers all three charge-motion mechanisms is presented for three-phase CCD's with gate lengths of 4 and 10 µ. The analysis shows that while the majority of the charge is transferred by means of the self-induced drift that follows a hyperbolic time dependence, the last few percent of the charge decays exponentially under the influence of the fringing field drift or thermal diffusion, depending on the design of the structure. The analysis shows that in CCD's made on relatively high resistivity substrates, the transfer by fringing-field drift can be very fast, such that transfer efficiencies of 99.99 percent are expected at 5- to 10- MHz bit rates for 10-µ gate lengths and at up to 100 MHz for 4-µ gate lengths.
121 citations
TL;DR: In this paper, the design and fabrication of a 96-element 3-phase linear charge-coupled device with a transfer efficiency of ∼95 percent over 288 transfers at a 1-MHz clock rate was described.
Abstract: The design and fabrication of a 96-element 3-phase linear charge-coupled device are described. A transfer efficiency of ∼95 percent over 288 transfers at a 1-MHz clock rate was measured. The use of the device as an analog delay line is demonstrated and its imaging properties are illustrated with reproductions of black and white text and a picture with gray scale. The results demonstrate the feasibility of using self-scanned imaging devices in practical applications. Configurations are presented for both an improved linear and an area imaging device. In both cases the problem of image smear, which occurs if stored charge is transferred along the light-sensitive region and if significant light integration takes place during this transfer, can be avoided.
120 citations
TL;DR: In this article, the free charge transfer characteristics of charge-coupled devices (CCD's) are analyzed in terms of the charge motion due to thermal diffusion, self-induced drift, and fringing field drift.
Abstract: The free charge-transfer characteristics of charge-coupled devices (CCD's) are analyzed in terms of the charge motion due to thermal diffusion, self-induced drift, and fringing field drift. The charge-coupled structures considered have separations between the gates equal to the thickness of the channel oxide. The effect of each of the above mechanisms on charge transfer is first considered separately, and a new method is presented for the calculation of the self-induced field. Then the results of a computer simulation of the charge-transfer process that simultaneously considers all three charge-motion mechanisms is presented for three-phase CCD's with gate lengths of 4 and 10 µ. The analysis shows that while the majority of the charge is transferred by means of the self-induced drift that follows a hyperbolic time dependence, the last few percent of the charge decays exponentially under the influence of the fringing field drift or thermal diffusion, depending on the design of the structure. The analysis shows that in CCD's made on relatively high resistivity substrates, the transfer by fringing-field drift can be very fast, such that transfer efficiencies of 99.99 percent are expected at 5- to 10- MHz bit rates for 10-µ gate lengths and at up to 100 MHz for 4-µ gate lengths.
112 citations
TL;DR: In this article, the effects of interface states in limiting the performance of surface channel charge-coupled devices (CCD's) are described and evaluated, and it is concluded that trapping effects are a limitation on the transfer efficiencies obtainable in surface channel CCDs, particularly, for example, at frequencies less than 1 MHz for devices having 10µm-long transfer electrodes.
Abstract: The several effects of interface states in limiting the performance of surface channel charge-coupled devices (CCD's) are described and evaluated. The limitations on transfer efficiency may be minimized by using a background charge in the device at all times. Experimental measurements of transfer inefficiency on three-phase devices and a two-phase device are presented and correlated with the predicted values, although measurements of the density and capture cross sections of interface states after device fabrication are required for accurate quantitative predictions of transfer inefficiencies. It is concluded that trapping effects are a limitation on the transfer efficiencies obtainable in surface channel charge-coupled devices, particularly, for example, at frequencies less than 1 MHz for devices having 10-µm-long transfer electrodes, but are not a direct limitation on the high-frequency performance. The effect of interface states in adding transfer noise onto the charge packets is also described, and is shown to be small, although in some devices it may reduce the signal-to-noise ratios that might otherwise be possible.
94 citations
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TL;DR: A new semiconductor device concept that consists of storing charge in potential wells created at the surface of a semiconductor and moving the charge over the surface by moving the potential minima is described.
Abstract: In this paper we describe a new semiconductor device concept. Basically, it consists of storing charge in potential wells created at the surface of a semiconductor and moving the charge (representing information) over the surface by moving the potential minima. We discuss schemes for creating, transferring, and detecting the presence or absence of the charge. In particular, we consider minority carrier charge storage at the Si-SiO 2 interface of a MOS capacitor. This charge may be transferred to a closely adjacent capacitor on the same substrate by appropriate manipulation of electrode potentials. Examples of possible applications are as a shift register, as an imaging device, as a display device, and in performing logic.
878 citations
TL;DR: To test the assumption that charge transfer efficiencies greater than 98 percent for transfer times less than 100 nsec were observed, devices were fabricated and measurements made.
Abstract: Structures have been fabricated consisting of closely spaced MOS capacitors on an n-type silicon substrate. By forming a depletion region under one of the electrodes, minority carriers (holes) may be stored in the resulting potential well. This charge may then be transferred to an adjacent electrode by proper manipulation of electrode potentials. The assumption that this transfer will take place in reasonable times with a small fractional loss of charge is the basis of the charge coupled devices described in the preceding paper,1 To test this assumption, devices were fabricated and measurements made. Charge transfer efficiencies greater than 98 percent for transfer times less than 100 nsec were observed.
185 citations
TL;DR: In this article, the electron-beam accessed target in camera tubes for the Picturephone® visual telephone set has been fabricated and their properties evaluated, and the efficiency for conversion of incident photons to electrons in the read-out circuit has been expressed by the efficiency of the photometric readout circuit, which is achieved by oxidizing or by diffusing phosphorus into the light-receiving surface to reduce the surface-recombination velocity.
Abstract: Silicon diode arrays for use as the electron-beam accessed target in camera tubes for the Picturephone® visual telephone set have been fabricated and their properties evaluated. These targets offer significant advantages over the antimony trisulfide target commonly used in vidicon-type tubes. But there are certain potential limitations which must be dealt with in developing a silicon target. Three of its critical requirements are adequate sensitivity to visible light, low dark current, and junction uniformity and freedom from defects across at least 300,000 diodes per square centimeter. Sensitivity to visible light is expressed here by the efficiency for conversion of incident photons to electrons in the read-out circuit. Conversion efficiencies exceeding 50 percent in the visible region have been achieved by oxidizing or by diffusing phosphorus into the light-receiving surface to reduce the surface-recombination velocity. Diode leakage currents of ≦1 × 10−13 A per diode are required, and are obtained for target voltages up to about 5 to 7 V. Surface generated current dominates in the 8-μ diameter diodes of the array, but this component of current can be reduced substantially by use of (100) surfaces or by hydrogen annealing. Visible defects in a picture can result from leaky diodes or oxide pinholes which cause bright spots, and diodes covered by oxide which cause dark spots. Our best targets show a video display with only a few defects; processing must be improved to eliminate defects completely.
61 citations