Solid-state imaging device
AssigneeWi-LAN, Inc.
InventorsMotonari Katsuno, Ryouhei Miyagawa, Masayuki Matsunaga
Life of this patent
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Abstract
Capacitance between a detection capacitor and a reset transistor is the largest among the capacitances between the detection capacitor and transistors placed around the detection capacitor. In order to reduce this capacitance, it is effective to reduce the channel width of the reset transistor. It is possible to reduce the effective channel width by distributing, in the vicinity of the channel of the reset transistor and the boundary line between an active region and an element isolation region, ions which enhance the generation of carriers of an opposite polarity to the channel.
Claims20
A solid-state imaging device comprising:
- a semiconductor substrate;
- a first photodiode, formed in the semiconductor substrate, that performs photoelectric conversion of incident light into signal charge;
- a first transfer transistor, formed on the semiconductor substrate, that transfers the signal charge accumulated in the first photodiode;
- a detection capacitor, formed on the semiconductor substrate, that accumulates the signal charge transferred by the first transfer transistor;
- and
- a reset transistor, formed on the semiconductor substrate, that discharges, into a drain, the signal charge accumulated in the detection capacitor;
- and
- a trench isolation region, formed on the semiconductor substrate, that surrounds a first active region of the first photodiode, a second active region of the first transfer transistor, a third active region of the detection capacitor and a fourth active region of the reset transistor,
- wherein ions are distributed in at least a first boundary between a portion of the fourth active region directly below a gate electrode of the reset transistor and the trench isolation region, the ions enhancing generation of carriers of an opposite polarity to a polarity of carriers in a channel below the gate electrode of the reset transistor, and
- wherein the reset transistor has an effective gate width shorter than an effective gate length.
A solid-state imaging device comprising:
- a semiconductor substrate;
- a photodiode, formed in the semiconductor substrate, that performs photoelectric conversion of incident light into signal charge;
- a transfer transistor, formed on the semiconductor substrate, that transfers the signal charge accumulated in the photodiode;
- a detection capacitor, formed on the semiconductor substrate, that accumulates the signal charge transferred by the transfer transistor;
- and
- a reset transistor, formed on the semiconductor substrate, that discharges, into a drain, the signal charge accumulated in the detection capacitor;
- and
- a trench isolation region, formed on the semiconductor substrate, that surrounds a first active region of the photodiode, a second active region of the transfer transistor, a third active region of the detection capacitor and a fourth active region of the reset transistor,
- wherein ions are distributed in at least a first boundary between a portion of the fourth active region directly below a gate electrode of the reset transistor and the trench isolation region, the ions enhancing generation of carriers of an opposite polarity to a polarity of carriers in a channel below the gate electrode of the reset transistor.
Dependencies are inferred from the claim text.