A charged coupled device structure (CCD) and a method for fabricating the CCD structure, which induces a maximum potential distribution difference by utilizing gate insulation films having different physical properties. The charged coupled device includes a semiconductor substrate, a first insulation layer formed on the semiconductor substrate, a plurality of first electrodes spaced at fixed intervals over the first insulation layer, a second insulation layer formed only between the plurality of first electrodes and the first insulation layer, a third insulation layer formed over the entire exposed surface of the first electrodes and the first insulation layer, and a plurality of second electrodes formed only on the surface area corresponding to spaces between the plurality of first electrodes. This gate insulation layers having different physical properties induces a maximum potential distribution difference in a semiconductor substrate with a dielectric constant difference between the insulation layers.
A method for manufacturing a solid-state imaging device includes forming a transfer channel portion and a light-receiving portion in a silicon substrate; forming a silicon oxide film on the silicon substrate; forming a silicon nitride film on the silicon oxide film, the silicon nitride film acting as a gate insulating film together with the silicon oxide film above the transfer channel portion and acting as an anti-reflection film above the light-receiving portion; forming a protection film on the silicon nitride film; forming a polysilicon film above the silicon nitride film via the protection film at least above the light-receiving portion; and etching the polysilicon film so as to form a transfer electrode above the transfer channel portion. The etching of the polysilicon film is carried out so that the polysilicon film is removed above the light-receiving portion while the protection portion remains.
A bidirectional horizontal charge transfer device and method includes a charge transfer area formed within a substrate, a plurality of first, second, third and fourth poly gates formed over the charge transfer area, an insulating layer formed between the first, second, third and fourth poly gates, a first clock signal applied to the first and second poly gates, a second clock signal applied to the third and fourth poly gates, and a biasing circuit for selectively applying a bias signal to the first and second clock signals so as to selectively change a charge transfer direction.
A solid-state imaging device comprises a plurality of pixels, each pixel comprising a semiconductor substrate of a first conductivity type; a photo-receiving portion of a second conductivity type formed in the semiconductor substrate; a detecting portion of the second conductivity type formed in the semiconductor substrate; an insulating film formed on the semiconductor substrate; a transfer gate electrode formed on the insulating film at lest between the photo-receiving portion and the detecting portion; and a read-out circuit, which is electrically connected to the detecting portion. A diffusion region of the same conductivity type as the detecting portion is formed in a region of the semiconductor substrate that is adjacent to an end of the detecting portion near the gate electrode and separate from the photo-receiving portion. An impurity concentration in the photo-receiving portion and an impurity concentration in the diffusion region are lower than an impurity concentration in the detecting portion. With this solid-state imaging device and with the method for producing the same, a solid-state imaging device is provided that reduces crystal defects in the photo-receiving portion and improves the output image quality.
A power MOSFET includes a drain zone which is disposed centrally in a substrate and is annularly surrounded by a lightly doped region of the same conductivity type as the drain zone. The lightly doped region is in turn annularly surrounded by a source zone. A gate electrode is also annular in shape and has an inner edge that overlaps the lightly doped region and an outer edge which overlaps the source zone.
A solid-state imaging device comprises a plurality of pixels, each pixel comprising a semiconductor substrate of a first conductivity type; a photo-receiving portion of a second conductivity type formed in the semiconductor substrate; a detecting portion of the second conductivity type formed in the semiconductor substrate; an insulating film formed on the semiconductor substrate; a transfer gate electrode formed on the insulating film at lest between the photo-receiving portion and the detecting portion; and a read-out circuit, which is electrically connected to the detecting portion. A diffusion region of the same conductivity type as the detecting portion is formed in a region of the semiconductor substrate that is adjacent to an end of the detecting portion near the gate electrode and separate from the photo-receiving portion. An impurity concentration in the photo-receiving portion and an impurity concentration in the diffusion region are lower than an impurity concentration in the detecting portion. With this solid-state imaging device and with the method for producing the same, a solid-state imaging device is provided that reduces crystal defects in the photo-receiving portion and improves the output image quality.
