Image sensing device and methods of manufacturing the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsMing-Hsien YANG, Chun-Hao CHOU, Kuo-Cheng LEE, Chung-Liang CHENG
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Abstract
Image sensing devices according to present disclosure include metal gate structures in a pixel device. Particularly, the metal gate structures include a ferroelectric layer and a conductive layer to form a negative capacitance device in the gate stack. As a result, the transistors in the pixel device have reduced threshold swing, improved gain and reduced threshold voltage shift. The pixel device according to the present disclosure includes a combination of metal gate and polycrystalline gate, which provides flexibility in pixel device design and improves performance.
Claims20
An image sensing device, comprising:
- an array of pixel devices, wherein at least one pixel device comprises:
- a semiconductor substrate including a radiation region, a floating diffusion region, two or more doped regions;
- a first gate structure disposed on the semiconductor substrate, wherein the first gate structure overlaps with the radiation region and the floating diffusion region;
- and
- a second gate structure disposed on the semiconductor substrate, wherein the second gate structure overlaps with the two or more doped regions, the first gate structure and the second gate structure include different arrangements of material layers.
An image sensing device, comprising:
- a photodetector comprising a first pinned layer and a second pinned layer;
- a transfer transistor comprising a transfer gate overlapping with a portion of the photodetector, wherein the transfer gate includes a first group of material layers;
- a source-follower transistor comprising a source-follower gate;
- a reset transistor comprising a reset gate;
- and
- a select transistor comprising a select gate, wherein at least one of the source-follower gate, the reset gate, and the select gate includes a second group of material layers different from the first group of material layers.
An image sensing device, comprising:
- a semiconductor substrate;
- a photodetector disposed in the semiconductor substrate;
- a floating diffusion region disposed in the semiconductor substrate;
- a transfer transistor comprising a transfer gate disposed on the semiconductor substrate, the transfer gate overlapping a portion of the photodetector;
- and
- a source-follower transistor, a reset transistor, and a select transistor disposed on the semiconductor substrate,
- wherein at least one of the source-follower transistor, the reset transistor, or the select transistor comprises a gate structure including a ferroelectric layer.
Dependencies are inferred from the claim text.