Linear image sensor

A linear image sensor comprising:

• a plurality of bipolar phototransistors arranged on a semiconductor substrate for reading picture information and outputting corresponding signals;
• a plurality of switching elements for reading signals output by the phototransistors, an input terminal of each switching element being connected to a respective phototransistor;
• a scanning circuit for driving control terminals of the switching elements;
• and a light-receiving MOS diode formed near each phototransistor and being covered with a light-transmissive gate electrode for passing at least a part of light incident thereon, a conductivity type of an inversion region of the light-receiving MOS diode being the same as that of a base region of the phototransistors, and the gate electrode of each light-receiving MOS diode covering at least a, part of a base region of an adjacent phototransistor through an isolation layer.

A linear image sensor comprising:

• a plurality of bipolar phototransistors arranged on a semiconductor substrate for reading picture information and outputting corresponding signals;
• a plurality of switching elements for reading the signals output by the phototransistors, an input terminal of each switching element being connected to a respective phototransistor;
• a scanning circuit for driving control terminals of the switching elements;
• and a light-receiving MOS diode formed near each phototransistor and being covered with a light-transmissive gate electrode for passing at least a part of light incident thereon and having an inversion region with the same conductivity type as that of a base region of the phototransistors;
• wherein the switching elements and the scanning circuit comprise MOS transistors, base regions of the phototransistors have a different conductivity type from that of the semiconductor substrate and are formed in well diffusion regions also forming well diffusion regions of the MOS transistors of the switching element and the scanning circuit, and diffusion regions are formed in a surface of the semiconductor substrate in the well diffusion regions, the diffusion regions having the same conductivity type as that of the well diffusion regions and having a higher impurity density.