Abstract: A back thinned CCD has at least first and second parallel n− signal channel segments and a p++ channel stop region between the signal channels.

Abstract: An optical detector includes a charge-coupled device (CCD). The CCD comprises an active cell for receiving a narrow beam of incident illumination and generating photoelectrons in response thereto, and a first stage readout register comprising a row of N transfer cells, where N>1. A first stage gate structure transfers charge packets consecutively from the active cell into the first stage readout register, whereby N successive charge packets are read into the N cells respectively of the first stage readout register. N second stage readout registers each comprise M transfer cells, where M>1, and a second stage gate structure transfers N charge packets from the N cells of the first stage readout register into respective first cells of the second stage readout registers and subsequently shifts the N charge packets from the respective first cells of the second stage readout registers to respective Mth cells thereof.

Abstract: A CCD which is designed and processed so that most of each pixel is covered only with an ultra-thin gate electrode so that the CCD can be frontside illuminated and still achieve good sensitivity in the ultra-violet and soft x-ray spectral range. More specifically, in the present invention, the usual three gate structure and corresponding polysilicon layers 1, 2 and 3 of conventional thickness are reduced in width and supplemented by a fourth ultra-thin layer of polysilicon dubbed herein, poly 4, that is deposited over the entire array. This fourth layer, poly 4, makes contact with poly 3, so that when poly 3 is driven, it also drives poly 4, thus allowing charge to collect and transfer as in a normal three phase CCD. However, because the deposition thickness of the poly 4 layer is on the order of 400 Angsttoms, as opposed to conventional thicknesses of 2000 to 5000 Angsttoms, poly 4 is essentially transparent to photons and thereby allows achievement of high quantum efficiency.

Abstract: Special purpose CCD designed for ultra low-noise imaging and spectroscopy applications that require subelectron read noise floors, wherein a non-destructive output circuit operating near its 1/f noise regime is clocked in a special manner to read a single pixel multiple times. Off-chip electronics average the multiple values, reducing the random noise by the square-root of the number of samples taken. Noise floors below 0.5 electrons rms are possible in this manner. In a preferred embodiment of the invention, a three-phase CCD horizontal register is used to bring a pixel charge packet to an input gate adjacent a floating gate amplifier. The charge is then repeatedly clocked back and forth between the input gate and the floating gate. Each time the charge is injected into the potential well of the floating gate, it is sensed non-destructively.

Abstract: A front-illuminated CCD of relative high quantum efficiency (QE) and high charge transfer efficiency (CTE) utilizes an open-phase region for receiving photons and two-phase gate regions (.phi..sub.1 and .phi..sub.2) for transferring electrons collected in one pixel to the next. The open-phase region is implanted with additional n-type elements (phosphorus) in order to increase the potential of the CCD channel in the open-phase region for collection of electrons and additionally implanted with concentrated and very shallow p-type elements (boron) to pin the surface of the n-channel in the open-phase region to OV, while gate region .phi..sub.1 and .phi..sub.2 are biased to -3.5V and driven to +10V by a two-phase transfer clock. The open pinned-phase (OPP) region thus permits two-phase transfer clocking and optimum reception of photons during the integration periods between transfer clock pulses.

Abstract: A backside illuminated CCD imaging sensor for reading out image charges from wells of the array of pixels is significantly improved for blue, UV, far UV and low energy x-ray wavelengths (1-5000.ANG.) by so overthinning the backside as to place the depletion edge at the surface and depositing a thin transparent metal film of about 10.ANG. on a native-quality oxide film of less than about 30.ANG. grown on the thinned backside. The metal is selected to have a higher work function than that of the semiconductor to so bend the energy bands (at the interface of the semiconductor material and the oxide film) as to eliminate wells that would otherwise trap minority carriers. A bias voltage may be applied to extend the frontside depletion edge to the interface of the semiconductor material with the oxide film in the event there is not sufficient thinning.

Abstract: A back illuminated, buried channel, multiphase charge-coupled device for imaging has a photosensitive volume bounded by silicon dioxide layers on both the front and back. The dark noise generated by these interfaces with the photosensitive volume is reduced by negative bias potential pinning the front at about -6V and the back at about -0.4V. To create fixed barrier phases at the front for accumulation within each pixel comprised of multiphase gates, positive ions are implanted at one phase gate while the others are phase clocked into channel inversion. Otherwise the phase clock of at least one gate must be controlled to provide accumulation to provide a "partial-inversion" technique. The negative bias at the back may be varied to adjust the quantum efficiency of the device, thus providing electronic shuttering.

Abstract: A method to significantly increase the quantum efficiency (QE) of a CCD (or similar photosensor) applied in the UV, far UV and low energy x-ray regions of the spectrum. The increase in QE is accomplished by overthinning the backside of a CCD substrate beyond the epitaxial interface and UV flooding the sensor prior to use. The UV light photoemits electrons to the thinned surface and charges the backside negatively. This in turn forms an accumulation layer of holes near the Si-SiO.sub.2 interface creating an electric field gradient in the silicon which directs the photogenerated signal to the frontside where they are collected in pixel locations and later transferred. An oxide film, in which the backside charge resides, must have quality equivalent to a well aged native oxide which typically takes several years to form under ambient conditions. To reduce the amount of time in growing an oxide of sufficient quality, a process has been developed to grow an oxide by using deionized steam at 95.degree. C.

Abstract: A method for promoting quantum efficiency (QE) of a CCD imaging sensor for UV, far UV and low energy x-ray wavelengths by overthinning the back side beyond the interface between the substrate and the photosensitive semiconductor material, and flooding the back side with UV prior to using the sensor for imaging. This UV flooding promotes an accumulation layer of positive states in the oxide film over the thinned sensor to greatly increase QE for either frontside or backside illumination. A permanent or semipermanent image (analog information) may be stored in a frontside SiO.sub.2 layer over the photosensitive semiconductor material using implanted ions for a permanent storage and intense photon radiation for a semipermanent storage.

Abstract: A backside illuminated CCD imaging sensor for reading out image charges from wells of the array of pixels is significantly improved for blue, UV, far UV and low energy x-ray wavelengths (1-5000.ANG.) by so overthinning the backside as to place the depletion edge at the surface and depositing a thin transparent metal film of about 10.ANG. on a native-quality oxide film of less than about 30.ANG. grown on the thinned backside. The metal is selected to have a higher work function than that of the semiconductor to so bend the energy bands (at the interface of the semiconductor material and the oxide film) as to eliminate wells that would otherwise trap minority carriers. A bias voltage may be applied to extend the frontside depletion edge to the interface of the semiconductor material with the oxide film in the event there is not sufficient thinning.

Abstract: A sensor is described for detecting the difference in phase of a pair of returned light pulse components, such as the two components of a light pulse of an optical gyro. In an optic gyro, the two light components have passed in opposite directions through a coil of optical fiber, with the difference in phase of the returned light components determining the intensity of light shining on the sensor. The sensor includes a CCD (charge coupled device) that receives the pair of returned light components to generate a charge proportional to the number of photons in the received light. The amount of the charge represents the phase difference between the two light components. At a time after the transmission of the light pulse and before the expected time of arrival of the interfering light components, charge accumulating in the CCD as a result of reflections from optical components in the system, are repeatedly removed from the CCD, by transferring out charges in the CCD and dumping these charges.