Photoelectric conversion apparatus and imaging system using the same

A photoelectric conversion apparatus comprising a pixel unit, the pixel unit including:

• a photoelectric conversion portion including at least a first photoelectric conversion element;
• a charge storing portion including at least a first charge storage element;
• a transistor;
• a floating diffusion portion configured such that a charge held by the charge storing portion is to be transferred to the floating diffusion portion;
• and
• a discharging portion configured to discharge a charge generated in the photoelectric conversion portion
• wherein the photoelectric conversion apparatus further comprises an isolation area configured to electrically isolate the charge storing portion, the isolation area including:
• a first isolation portion including a PN junction, and
• a second isolation portion that includes an insulator arranged between the first charge storage element and at least a part of the transistor, and
• wherein the PN junction and the insulator are arranged in different locations,
• a gate electrode is provided between the first photoelectric conversion element and the first charge storage element,
• the gate electrode, the first photoelectric conversion element, and the first charge storage element form a transistor having a buried channel,
• the first photoelectric conversion element includes a first semiconductor region of a first conductivity type,
• the transistor includes a source region and a drain region of the first conductivity type,
• an impurity concentration of at least one of the source and drain regions is higher than that of the first semiconductor region,
• the transistor is one of a transfer transistor configured to transfer a charge held by the charge storing portion, a reset transistor and an amplification transistor,
• the discharging portion includes an overflow drain and a gate electrode arranged between the overflow drain and the photoelectric conversion portion,
• the first charge storage element includes a second semiconductor region of the first conductivity type,
• a third semiconductor region of a second conductivity type is arranged under the second semiconductor region,
• the third semiconductor region is configured to provide a barrier for reducing an intrusion of a charge into the second semiconductor region, and
• a fourth semiconductor region of the second conductivity type is provided between the first charge storage element and the insulator included in the second isolation portion.

A photoelectric conversion apparatus comprising a pixel unit, the pixel unit including:

• a photoelectric conversion portion including at least a first photoelectric conversion element;
• a charge storing portion including at least a first charge storage element;
• and
• a transistor,
• wherein the photoelectric conversion apparatus further comprises an isolation area for electrically isolating the charge storing portion, the isolation area including:
• a first isolation portion including a PN junction arranged between the first charge storage element and a photoelectric conversion portion of an adjacent pixel unit;
• and
• a second isolation portion including an insulator arranged between the first charge storage element and at least a part of the transistor.

A photoelectric conversion apparatus comprising a pixel unit, the pixel unit including:

• a photoelectric conversion portion including at least a first photoelectric conversion element;
• a charge storing portion including at least a first charge storage element;
• and
• a transistor,
• wherein the photoelectric conversion apparatus further comprises an isolation area for electrically isolating the charge storing portion, the isolation area including:
• a first isolation portion including a PN junction arranged between the first charge storage element and a charge storing portion of an adjacent pixel unit;
• and
• a second isolation portion including an insulator arranged between the first charge storage element and at least a part of the transistor.

A photoelectric conversion apparatus comprising:

• a first photoelectric conversion element;
• a first charge storage element including a semiconductor region of a first conductivity type arranged so as to hold a charge generated in the first photoelectric conversion element;
• a transistor;
• and
• an isolation area for electrically isolating the first charge storage element,
• wherein the isolation area includes:
• a semiconductor region of a second conductivity type providing a PN junction together with the semiconductor region of the first conductivity type;
• and
• an insulator arranged between the first charge storage element and at least a part of the transistor.