Abstract:
A CMOS active pixel sensor (APS) cell structure having dual workfunction transfer gate device and method of fabrication. The transfer gate device comprises a dielectric layer formed on a substrate and a dual workfunction gate conductor layer formed on the dielectric layer comprising a first conductivity type doped region and an abutting second conductivity type doped region. The transfer gate device defines a channel region where charge accumulated by a photosensing device is transferred to a diffusion region. A silicide structure is formed atop the dual workfunction gate conductor layer for electrically coupling the first and second conductivity type doped regions. In one embodiment, the silicide contact is smaller in area dimension than an area dimension of said dual workfunction gate conductor layer. Presence of the silicide strap prevents the diodic behavior from allowing one or the other side of the gate to float to an indeterminate voltage.
Abstract:
The image qualify of an image frame from a CMOS image sensor array operated in global shutter mode may be enhanced by dispersing or randomizing the noise introduced by leakage currents from floating drains among the rows of the image frame. Further, the image quality may be improved by accounting for time dependent changes in the output of dark pixels in dark pixel rows or dark pixel columns. In addition, voltage and time dependent changes in the output of dark pixels may also be measured to provide an accurate estimate of the noise introduced to the charge held in the floating drains. Such methods may be employed individually or in combination to improve the quality of the image.
Abstract:
A pixel sensor cell having a semiconductor substrate having a surface; a photosensitive element formed in a substrate having a non-laterally disposed charge collection region entirely isolated from a physical boundary including the substrate surface. The photosensitive element comprises a trench having sidewalls formed in the substrate of a first conductivity type material; a first doped layer of a second conductivity type material formed adjacent to at least one of the sidewalls; and a second doped layer of the first conductivity type material formed between the first doped layer and the at least one trench sidewall and formed at a surface of the substrate, the second doped layer isolating the first doped layer from the at least one trench sidewall and the substrate surface. In a further embodiment, an additional photosensitive element is provided that includes a laterally disposed charge collection region that contacts the non-laterally disposed charge collection region of the photosensitive element and underlies the doped layer formed at the substrate surface.
Abstract:
A global shutter compatible pixel circuit comprising a reset gate (RG) transistor is provided in which a dynamic voltage is applied to the drain of the reset gate transistor in order to reduce a floating diffusion (FD) leakage therethrough during signal hold time. The drain voltage of the reset gate transistor is held at a lower voltage than a circuit supply voltage to minimize the off-state leakage through the RG transistor, thus reducing the change in the voltage at the floating diffusion during the signal hold time. In addition, a design structure for such a circuit providing a dynamic voltage to the drain of a reset gate of a pixel circuit is also provided.
Abstract:
A CMOS active pixel sensor (APS) cell structure having dual workfunction transfer gate device and method of fabrication. The transfer gate device comprises a dielectric layer formed on a substrate and a dual workfunction gate conductor layer formed on the dielectric layer comprising a first conductivity type doped region and an abutting second conductivity type doped region. The transfer gate device defines a channel region where charge accumulated by a photosensing device is transferred to a diffusion region. A silicide structure is formed atop the dual workfunction gate conductor layer for electrically coupling the first and second conductivity type doped regions. In one embodiment, the silicide contact is smaller in area dimension than an area dimension of said dual workfunction gate conductor layer. Presence of the silicide strap prevents the diodic behavior from allowing one or the other side of the gate to float to an indeterminate voltage.
Abstract:
A pixel sensor cell having a semiconductor substrate having a surface; a photosensitive element formed in a substrate having a non-laterally disposed charge collection region entirely isolated from a physical boundary including the substrate surface. The photosensitive element comprises a trench having sidewalls formed in the substrate of a first conductivity type material; a first doped layer of a second conductivity type material formed adjacent to at least one of the sidewalls; and a second doped layer of the first conductivity type material formed between the first doped layer and the at least one trench sidewall and formed at a surface of the substrate, the second doped layer isolating the first doped layer from the at least one trench sidewall and the substrate surface. In a further embodiment, an additional photosensitive element is provided that includes a laterally disposed charge collection region that contacts the non-laterally disposed charge collection region of the photosensitive element and underlies the doped layer formed at the substrate surface.
Abstract:
An imaging circuit, an imaging sensor, and a method of imaging. The imaging cell circuit including one or more imaging cell circuits, each imaging cell circuit comprising: a transistor having a floating body for holding charge generated in the floating body in response to exposure of the floating body to electromagnetic radiation; means for biasing the transistor wherein an output of the transistor is responsive to the electromagnetic radiation; and means for selectively connecting the floating body to a reset voltage supply.
Abstract:
A structure (and method for forming the same) for an image sensor cell. The structure includes (a) a semiconductor substrate; (b) a charge collection well on the substrate, the charge collection well comprising a semiconductor material doped with a first doping polarity; (c) a surface pinning layer on and in direct physical contact with the charge collection well, the surface pinning layer comprising a semiconductor material doped with a second doping polarity opposite to the first doping polarity; and (d) an electrically conducting push electrode being in direct physical contact with the surface pinning layer but not being in direct physical contact with the charge collection well.
Abstract:
A design structure for an integrated radio frequency (RF) filter on a backside of a semiconductor substrate includes: a device on a first side of a substrate; a radio frequency (RF) filter on a backside of the substrate; and at least one substrate conductor extending from the front side of the substrate to the backside of the substrate and electrically coupling the RF filter to the device.
Abstract:
A method of preventing blooming in a pixel array includes affecting an amount of light that impinges on a photoelectric conversion element by adjusting a transmissivity of an electrochromic element based on an output of the photoelectric conversion element.