PN-structured gate demodulation pixel

Abstract

A novel photo-sensitive element for electronic imaging purposes and, in this context, is particularly suited for time-of-flight 3D imaging sensor pixels. The element enables charge-domain photo-detection and processing based on a single gate architecture. Certain regions for n and p-doping implants of the gates are defined. This kind of single gate architecture enables low noise photon detection and high-speed charge transport methods at the same time. A strong benefit compared to known pixel structures is that no special processing steps are required such as overlapping gate structures or very high-ohmic poly-silicon deposition. In this sense, the element relaxes the processing methods so that this device may be integrated by the use of standard CMOS technology for example. Regarding time-of-flight pixel technology, a major challenge is the generation of lateral electric fields. The element allows the generation of fringing fields and large lateral electric fields.

Description

[0001] related application [0002] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application 61 / 613,363, filed March 20, 2012, which is hereby incorporated by reference in its entirety. Background of the invention [0003] Generally, two different types of devices have been used in the past for light detection in the charge domain: The first type of device is the pinned photodiode (PPD) (see, e.g., Nobukazu Teranishi et al., “No image lag photodiode structure in the interline CCD image sensor (image-free photodiode structure in an interlaced CCD image sensor)", IEEE, 1982), which is available in today's complementary metal-oxide-semiconductor (CMOS) process technology; and the second type of device uses MOS Gate structures, which can be fabricated in CMOS technology or optimized Charge Coupled Device (CCD) technology. [0004] Pinned photodiodes typically have two implants in the substrate whose doping concentrations are chosen in suc...

AI Technical Summary

Problems solved by technology

[0012] All PPD-based approaches share a common drawback: their overall inflexibility in drift voltage control compared to gate-based approaches, since the pinning voltage is predetermined by the doping concentration and cannot be obtained from an external source. controlled

The discretization of the potential gradient caused by the use of several gates always leads to a step function, but never to a perfectly constant gradient

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