Aptina Imaging Corporation

Semiconductor Components Industries, LLC

Xia Zhao

Hirofumi Komori

Jaroslav Hynecek

Chung Chun Wan

Gennadiy A Agranov

Xiangli Li

Hui Tian

Paul Perez

Wei Gao

The invention describes image sensor array pixels with global and rolling shutter capabilities that utilize multiple BCMD transistors for storing and sensing charge for a single photodiode. This configuration improves the Dynamic Range (DR) of the sensor, by allowing sensing different image signals from a single pixel without saturation, a low level signal with long integration time followed by a high level signal with short integration time. Signal processing circuits can process these signals into a single Wide Dynamic Range (WDR) output. Further disclosed are pixels that use multiple-gate BCMD transistors for charge storage and sensing having multiple concentric gates, which allows changing the conversion gain of the BCMD transistors. Variable conversion gain is a useful feature when building WDR sensors since low conversion gain and high well capacity allows detection of high level signals and, at the same time, low level signals with high conversion gain and low noise.

Global shutter bulk charge modulated device

An image sensor having pixel circuitry operable in multiple gain modes is provided. The pixel circuitry may include first and second floating diffusion (FD) regions, a first photodiode coupled to the first FD region via a first transfer gate, a second photodiode coupled to the first FD region via a second transfer gate, a third photodiode coupled to the second FD region via a third transfer gate, and a fourth photodiode coupled to the second FD region via a fourth transfer gate. The first FD region may be coupled to the second FD region via first and second control transistors. The control transistors may be connected to a shared reset transistor. During readout, both control transistors may be deactivated to provide a high gain mode, only one transistor may be activated to provide an intermediate gain mode, or both control transistors may be activated to provide a low gain mode.

Triple conversion gain image sensor pixels

The invention describes in detail a solid-state CMOS image sensor, specifically a CMOS image sensor pixel that has stacked photo-sites, high sensitivity, and low dark current. The pixels have incorporated therein special potential barriers under the standard pinned photodiode region that diverts the photo-generated electrons from a deep region within the silicon bulk to separate storage structures located at the surface of the silicon substrate next to the pinned photodiode. The storage structures are p channel BCMD transistors that are biased to a low dark current generation mode during a charge integration period. The signal readout from the BCMD is nondestructive, therefore, without kTC noise generation. Thus a single pixel is capable of detecting several color-coded signals while using fewer or without using any light absorbing color filters on top of the pixel. The image sensors constructed with the stacked photo-sites with BCMD readout have higher pixel densities, higher resolution, higher sensitivity, very low dark current, and no color aliasing if at least three depth encoded signals are read from a single photodiode. The pixels having stacked photo-sites with BCMD readout are particularly suitable for a CMOS image sensor that is illuminated from the back side.

Stacked pixels for high resolution CMOS image sensors with BCMD charge detectors

The invention describes a solid-state CMOS image sensor array and discloses image sensor array pixels with global and rolling shutter capabilities that utilize multiple BCMD transistors for a single photodiode, for charge storage and sensing. Thus, the valuable pixel area saved by employing the BCMD transistor for charge storage and sensing is used by placing several BCMD transistors coupled to one photodiode. This increases the Dynamic Range (DR) of the sensor, since the same photodiode can integrate charge for different integration times, both long and short. This allows sensing of two different image signals from a single pixel without saturation, a low level signal with long integration time followed by a high level signal with short integration time. The signal processing circuits located at the periphery of the array can then process these signals into a single Wide Dynamic Range (WDR) output. Further disclosed is an image sensor array with pixels that use BCMD transistors for charge storage and sensing having multiple concentric gates, which allows changing the conversion gain of the BCMD transistors by applying various biases to the gates. Variable conversion gain is a useful feature when building WDR sensors since low conversion gain and high well capacity allows detection of high level signals and the same structure can be used to detect, at the same time, low level signals with high conversion gain and thus low noise.

CMOS image sensor with global shutter, rolling shutter, and a variable conversion gain, having pixels employing several BCMD transistors coupled to a single photodiode and dual gate BCMD transistors for charge storage and sensing

The present invention relates to a junction gate photo-diode (JGP) pixel that includes a JGP for accumulating charge in response to impinging photons. The JGP is positioned on a substrate and includes a top n layer, a middle p layer and a bottom n layer forming a n-p-n junction, and a control terminal coupled to the top n layer. Also included is a floating diffusion (FD) positioned on the substrate and coupled to a pixel output line through an amplifier. Also included is a pinned barrier (PB) positioned on the substrate between the JGP and the FD, the PB temporarily blocks charge transfer between the JGP and the FD. The accumulated charge is transferred from the JGP to FD by applying a control voltage to the JGP control terminal.

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Campbell, CA, United States of America

Xia Zhao