Image sensor having a source follower transistor with a multi-thickness gate dielectric

    公开(公告)号:US10964738B2

    公开(公告)日:2021-03-30

    申请号:US16149544

    申请日:2018-10-02

    Abstract: An image sensor includes one or more photodiodes disposed in a semiconductor material to receive image light and generate image charge, and a floating diffusion to receive the image charge from the one or more photodiodes. One or more transfer transistors is coupled to transfer image charge in the one or more photodiodes to the floating diffusion, and a source follower transistor is coupled to amplify the image charge in the floating diffusion. The source follower includes a gate electrode (coupled to the floating diffusion), source and drain electrodes, and an active region disposed in the semiconductor material between the source and drain electrodes. A dielectric material is disposed between the gate electrode and the active region and has a first thickness and a second thickness. The second thickness is greater than the first thickness, and the second thickness is disposed closer to the drain electrode than the first thickness.

    Enhanced shutter efficiency time-of-flight pixel

    公开(公告)号:US11032496B2

    公开(公告)日:2021-06-08

    申请号:US16517904

    申请日:2019-07-22

    Inventor: Eric Webster

    Abstract: A time-of-flight pixel array comprises multiple pixel cells. The pixel cell comprises a light collection region, a light shielded region, and a deep trench isolation (DTI) structure that encircles the light collection region to prevent light from entering the light shielded region. Photogate in the light collection region is disposed above a photodiode to accumulate the photo-generated electrical charges. A doped region disposed near the photogate collects the attracted charges. The doped region extends to the light shielded region and transfers the collected charges to a floating diffusion through a shutter transistor also in the light shielded region. DTI or similar structures are deployed to the entire pixel array to prevent light from exchanging between different light collection regions and light from entering the light shielded regions of all pixel cells. Interference between the shielded regions of different pixel cells is also minimized.

    Enhanced Shutter Efficiency Time-of-Flight Pixel

    公开(公告)号:US20210029311A1

    公开(公告)日:2021-01-28

    申请号:US16517904

    申请日:2019-07-22

    Inventor: Eric Webster

    Abstract: A time-of-flight pixel array comprises multiple pixel cells. The pixel cell comprises a light collection region, a light shielded region, and a deep trench isolation (DTI) structure that encircles the light collection region to prevent light from entering the light shielded region. Photogate in the light collection region is disposed above a photodiode to accumulate the photo-generated electrical charges. A doped region disposed near the photogate collects the attracted charges. The doped region extends to the light shielded region and transfers the collected charges to a floating diffusion through a shutter transistor also in the light shielded region. DTI or similar structures are deployed to the entire pixel array to prevent light from exchanging between different light collection regions and light from entering the light shielded regions of all pixel cells. Interference between the shielded regions of different pixel cells is also minimized.

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