Solid-state image sensor

A solid-state image sensor comprising:

• a plurality of pixel units arranged on a semiconductor substrate layer having a first conductivity type in a matrix format, each of said pixel units including a photodiode having a p-n junction formed between the substrate layer and a first diffusion layer which has a second conductivity type and is formed in the substrate layer and configured to convert photoelectrically image-sensing light, an amplification transistor comprising a MOS transistor configured to extract a signal obtained by the photodiode, a selection transistor comprising a MOS transistor configured to select said pixel unit, and a reset translator comprising a MOS transistor configured to reset a signal charge in the photodiode;
• a scanning circuit configured to read and transfer sequentially the signals obtained by the photoelectric conversion portions of said plurality of pixel units, said scanning circuit including a plurality of signal wiring lines connected to the amplification transistors configured to transfer the signals from said pixel units, a plurality of address lines connected to the selection transistors configured to select said pixel units, a plurality of reset lines connected to the reset translators configured to selectively reset said pixel units, and a driving circuit configured to drive the signal wiring lines, the address lines, and the reset lines;
• and
• element isolation regions configured to isolate said pixel units from each other, said element isolation region including a bottom portion positioned deeper than a bottom portion of said first diffusion layer.

A solid-state image sensor comprising:

• a plurality of pixel units arranged on a semiconductor substrate layer of a first conductivity type in a matrix format, each of said pixel units including a photoelectric conversion portion configured to convert photoelectrically image-sensing light and a signal extraction portion including a field-effect transistor configured to extract a signal from said photoelectric conversion portion, said photoelectric conversion portion comprising a photodiode including a p-n junction formed between the substrate layer and a first diffusion layer that has a second conductivity type and is formed in the substrate layer;
• a scanning circuit connected to the signal extraction portions and configured to read and transfer sequentially the signals obtained by the photoelectric portions of said plurality of pixel units;
• and
• element isolation regions configured to isolate said pixel units from each other, each pixel element isolation region including a bottom portion positioned deeper than a bottom portion of said first diffusion layer,
• wherein said element isolation region comprises an insulating oxide film formed on the substrate layer, and a second diffusion layer that is formed in the substrate layer immediately below the oxide film and has the first conductivity type and a carrier impurity concentration higher than that of the substrate layer.

A solid-state image sensor comprising:

• a plurality of pixel units arranged on a semiconductor substrate layer of a first conductivity type in a matrix format, each of said pixel units including a photoelectric conversion portion configured to convert photoelectrically image-sensing light and a signal extraction portion including a field-effect transistor configured to extract a signal from said photoelectric conversion portion, said photoelectric conversion portion comprising a photodiode including a p-n junction formed between the substrate layer and a first diffusion layer that has a second conductivity type and is formed in the substrate layer;
• a scanning circuit connected to the signal extraction portions and configured to read and transfer sequentially the signals obtained by the photoelectric portions of said plurality of pixel units;
• and
• element isolation regions configured to isolate said pixel units from each other, each pixel element isolation region including a bottom portion positioned deeper than a bottom portion of said first diffusion layer,
• wherein said element isolation region comprises a trench formed in the substrate layer and an insulating layer buried in the trench.