Image sensing device using MOS-type image sensing element whose threshold voltage of charge transfer switch and reset switch is different from that of signal output transistor

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and the threshold voltage of said field effect transistor for outputting signals is made different from the threshold voltages of said first switch and said second switch by making an impurity concentration in channel region of said field effect transistor be different from impurity concentrations in channel regions of said first switch and said second switch.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein the threshold voltage of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by doping all the channel regions of said field effect transistor for outputting a signal, said first switch, and said second switch with dopant of a predetermined impurity concentration, first, then further doping a channel region of said field effect transistor for outputting a signal.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and the threshold of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by making well region of said field effect transistor for outputting a signal have an impurity concentration different from well regions of said first switch and said second switch.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and the threshold of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by making the gate dielectric film of said field effect transistor for outputting a signal have a thickness different from thickness of gate dielectric films of said first switch and said second switch.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and the threshold of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by making the gate dielectric film of said field effect transistor for outputting a signal with material having dielectric constant different from dielectric constants of gate dielectric films of said first switch and said second switch.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and said field effect transistor for outputting a signal, said first switch and said second switch are formed on different well regions which are isolated from each other, and the threshold of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by applying a voltage, different from a voltage applied to the well regions of said first switch and second switch, to said field effect transistor for outputting a signal.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and the threshold of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by making said field effect transistor for outputting a signal have gate length different from gate length of said first switch and said second switch.

A photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having a gate area, a first switch for transferring charge generated by said photoelectric conversion element to the gate area of the field effect transistor for outputting a signal corresponding to the charge stored in the gate area, and a second switch, for resetting the gate area of said field effect transistor,

• wherein threshold voltages of said first switch and said second switch are made different from a threshold voltage of said field effect transistor, and
• wherein said first switch and said second switch are field effect transistors, and the threshold of said field effect transistor for outputting a signal is made different from the threshold voltages of said first switch and said second switch by making said field effect transistor for outputting a signal have gate width different from gate width of said first switch and said second switch.