Optical sensor, signal reading method therefor, solid-state imaging device, and signal reading method therefor

An optical sensor comprising:

• a light-receiving element (PD), a transfer switch (T), an overflow switch (S), and a reset switch (R) connected in series in this order,
• a floating diffusion capacitor (CFD) and a source follower switch (SF) connected to wiring between the transfer switch (T) and the switch (S);
• and
• a lateral overflow integration capacitor (CLOFIC) connected to wiring between the switch (S) and the reset switch (R);
• wherein
• the source follower switch (SF) is a MOS transistor;
• and
• the transfer switch (T) is a non-LDD/MOS transistor for which the impurity concentration of a drain region is 50% less than an impurity concentration of a source region of the source follower switch (SF).

An optical sensor comprising:

• a light-receiving element, storage capacitors that store a charge, a transfer switch for transferring to the storage capacitors a charge generated by light input to the light-receiving element, and a pixel signal output line per pixel;
• and
• a signal reading path connected to the pixel signal output lines;
• wherein:
• the storage capacitors are a floating diffusion capacitor and a lateral overflow integration capacitor, and the transfer switch is a non-LDD/MOS transistor for which the impurity concentration of a drain region thereof is 1×1020 impurities/cm3 or less;
• the signal reading path receives a first pixel output signal subjected to charge-voltage conversion by the floating diffusion capacitor, and a second pixel output signal subjected to charge-voltage conversion by combining the floating diffusion capacitor and the lateral overflow integration capacitor;
• and
• the first pixel output signal is amplified in the signal reading path by a plurality of amplifiers that include at least one amplifier having an amplification factor greater than 1.

A multi-pixel optical sensor comprising:

• a light-receiving element, storage capacitors that store a charge, and a transfer switch for transferring to the storage capacitors a charge generated by light input to the light-receiving element, the storage capacitors being a floating diffusion capacitor and a lateral overflow integration capacitor, and the transfer switch being a non-LDD/MOS transistor for which an impurity concentration of a drain region thereof is 1×1020 impurities/cm3 or less;
• pixel column portions having pixel portions planarly arranged therein;
• a pixel signal output line having the pixel column portions connected sequentially thereto;
• and
• a signal reading path portion connected to the pixel signal output at a position downstream from a position where a last pixel portion of an array of the pixel column portions of the pixel signal output line is connected;
• wherein:
• the signal reading path portion comprises a plurality of signal paths, and at least two of the plurality of signal paths are respectively provided with amplification functions having different amplification factors;
• and
• at least one of the amplification functions has an amplification factor greater than 1.

A signal reading method for an optical sensor comprising:

• a light-receiving element, storage capacitors that store a charge, and a transfer switch for transferring to the storage capacitors a charge generated by light input to the light-receiving element, per pixel portion;
• a sensor portion in which the storage capacitors are a floating diffusion capacitor and a lateral overflow integration capacitor, and the transfer switch is a non-LDD/MOS transistor for which the impurity concentration of a drain region thereof is 1×1020 impurities/cm3 or less;
• a pixel signal output line having each pixel portion connected thereto;
• and
• a signal reading path connected to the pixel signal output line;
• the signal reading method comprising the steps of:
• forming a first pixel output signal by converting a charge of a charge amount that contributes to reading by the floating diffusion capacitor to voltage, forming a second pixel output signal by combining the floating diffusion capacitor and the lateral overflow integration capacitor and converting a charge of a charge amount that contributes to reading to voltage, and inputting these two pixel output signals to the signal reading path;
• wherein:
• the first pixel output signal is amplified in the signal reading path by a plurality of amplifiers that include at least one amplifier having an amplification factor greater than 1.

An imaging device comprising:

• a light-receiving element (PD), a transfer switch (T), an overflow switch (S), and a reset switch (R) connected in series in that order, a floating diffusion capacitor (CFD) and a source follower switch (SF) connected to wiring between the transfer switch (T) and the switch (S), and a lateral overflow integration capacitor (CLOFIC) connected to wiring between the switch (S) and the reset switch (R), wherein:
• the source follower switch (SF) is a MOS transistor,
• the transfer switch (T) comprises a plurality of pixel portions serving as non-LDD/MOS transistors for which the impurity concentration of a drain region is 50% less than an impurity concentration of a source region of the source follower switch (SF), and the light-receiving elements (PD) of the plurality of pixel portions are arranged two-dimensionally and comprise a pixel array;
• the plurality of pixel portions comprises pixel column output signal lines that are sequentially connected;
• the pixel column output signal line comprises a column circuit portion connected thereto, and the column circuit portion receives a first pixel output signal subjected to charge-voltage conversion by the floating diffusion capacitor, and a second pixel output signal subjected to charge-voltage conversion by combining the floating diffusion capacitor and the lateral overflow integration capacitor;
• and
• the first pixel output signal is amplified in the signal reading path by a plurality of amplifiers that include at least one amplifier having an amplification factor greater than 1.

A signal reading method for an imaging device comprising:

• a light-receiving element (PD), a transfer switch (T), an overflow switch (S), and a reset switch (R) connected in series in that order, a floating diffusion capacitor (CFD) and a source follower switch (SF) connected to wiring between the transfer switch (T) and the switch (S), and a lateral overflow integration capacitor (CLOFIC) connected to wiring between the switch (S) and the reset switch (R), wherein:
• the source follower switch (SF) is a MOS transistor, the transfer switch (T) comprises a plurality of pixel portions serving as non-LDD/MOS transistors for which the impurity concentration of a drain region is 50% less than an impurity concentration of a source region of the source follower switch (SF), the light-receiving elements (PD) of the plurality of pixel portions are arranged two-dimensionally to constitute a pixel array, the plurality of pixel portions is sequentially connected to a pixel column output signal line, and the pixel column output signal line is connected to a column circuit portion;
• the signal reading method comprising the steps of:
• forming a first pixel output signal by converting a charge of a charge amount that contributes to reading by the floating diffusion capacitor to voltage, forming a second pixel output signal by combining the floating diffusion capacitor and the lateral overflow integration capacitor and converting a charge of a charge amount that contributes to reading to voltage, and inputting these two pixel output signals to the signal reading path;
• wherein:
• the first pixel output signal is amplified in the signal reading path by a plurality of amplifiers that include at least one amplifier having an amplification factor greater than 1.