There is provided a light receiving element and a ranging system which achieve reduction in the number of signal lines which output detection signals. The light receiving element includes a pixel array in which a plurality of pixels is arranged in a matrix, and a pixel driving unit configured to control respective pixels of the pixel array to be active pixels or non-active pixels, in which the pixel driving unit controls the pixels to be the active pixels in units of spot including NM pixels (N>0, M>0, where N and M do not become 1 at a same time), and one signal line which outputs a detection signal is disposed at the pixel array for a plurality of spot constituent pixels of a same type within one unit where the one unit includes LL pixels (L>1).

An avalanche photodiode sensor according to an embodiment includes a first semiconductor substrate and a second semiconductor substrate bonded to a first surface of the first semiconductor substrate, wherein the first semiconductor substrate includes a plurality of photoelectric conversion portions arranged in a matrix and an element separation portion for element-separating the plurality of photoelectric conversion portions from each other, the plurality of photoelectric conversion portions include a first photoelectric conversion portion, the element separation portion has a first element separation region and a second element separation region, the first photoelectric conversion portion is arranged between the first element separation region and the second element separation region, the first semiconductor substrate further includes a plurality of concave-convex portions arranged on a second surface opposite to the first surface and arranged between the first element separation region and the second element separation region, and the second semiconductor substrate includes a reading circuit connected to each of the photoelectric conversion portions.

The present disclosure relates to an integrated chip including a substrate and a pixel. The pixel includes a photodetector. The photodetector is in the substrate. The integrated chip further includes a first inner trench isolation structure and an outer trench isolation structure that extend into the substrate. The first inner trench isolation structure laterally surrounds the photodetector in a first closed loop. The outer trench isolation structure laterally surrounds the first inner trench isolation structure along a boundary of the pixel in a second closed loop and is laterally separated from the first inner trench isolation structure. Further, the integrated chip includes a scattering structure that is defined, at least in part, by the first inner trench isolation structure and that is configured to increase an angle at which radiation impinges on the outer trench isolation structure.

Disclosed is a single photon avalanche diode comprises a first well having a first conductivity type, a heavily doped region provided on the first well, a guard ring surrounding the heavily doped region, and a second region formed between the first well and the heavily doped region and configured to multiply charge carriers. The heavily doped region and the guard ring have a second conductivity type different from the first conductivity type. The second region extends onto a boundary between a lower portion of the guard ring and the first well.

A photodetection element comprises a substrate having a first surface and a second surface opposite to each other, a first node region within the substrate and having a first conductivity type, a second node region within the substrate spaced apart from the first node region and having a second conductivity type different from the first conductivity type, and an avalanche multiplication region formed between the first node region and the second node region. The first node region, the avalanche multiplication region, and the second node region are arranged along a first direction parallel to the first surface.

A photoelectric conversion element includes a first semiconductor region of a first conductivity type provided in contact with a first face of a semiconductor layer, a second semiconductor region of a second conductivity type provided closer to a second face of the semiconductor layer than the first semiconductor region, and a third semiconductor region provided closer to the second face than the second semiconductor region. The first semiconductor region and the second semiconductor region constitute an avalanche photodiode, and the avalanche photodiode is configured to multiply a signal charge generated in the third semiconductor region. A width in a depth direction of a region having an effective impurity density of 110.sup.16 cm.sup.3 or more of the second semiconductor region is 0.5 m or less.

A lateral Ge/Si APD constructed on a silicon-on-insulator wafer includes a silicon device layer having regions that are doped to provide a lateral electric field and an avalanche region. A region having a modest doping level is in contact with a germanium body. There are no metal contacts made to the germanium body. The electrical contacts to the germanium body are made by way of the doped regions in the silicon device layer.

A method of detecting an optical signal, comprising the steps of: providing an avalanche photodiode (APD) comprising a multiplication region capable of amplifying an electric current, said multiplication region, in operation, having a first ionization rate for electrons and a second ionization rate for holes, wherein said first ionization rate is different in magnitude from said second ionization rate, and exposure to the optical signal causes an impulse response; exposing the APD to a modulating optical signal; providing an external circuit that induces an APD bias to the multiplication region; providing an external circuit for amplifying and processing an electric signal from the avalanche photodiode; and modulating the APD bias in a manner that is correlated with the optical signal.

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as holes, effectively increase the absorption of the photons. Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s at photons with wavelengths of 850 nm, and with quantum efficiencies of approximately 90% or more. Their thickness dimensions allow them to be conveniently integrated on the same Si chip with CMOS, BiCMOS, and other electronics, with resulting packaging benefits and reduced capacitance and thus higher speeds.

A photodetecting device includes a semiconductor substrate, a plurality of avalanche photodiodes each including a light receiving region disposed at a first principal surface side of the semiconductor substrate, the avalanche photodiodes being arranged two-dimensionally at the semiconductor substrate, and a through-electrode electrically connected to a corresponding light receiving region. The through-electrode is provided in a through-hole penetrating through the semiconductor substrate in an area where the plurality of avalanche photodiodes are arranged two-dimensionally. At the first principal surface side of the semiconductor substrate, a groove surrounding the through-hole is formed between the through-hole and the light receiving region adjacent to the through-hole. A first distance between an edge of the groove and an edge of the through-hole surrounded by the groove is longer than a second distance between the edge of the groove and an edge of the light receiving region adjacent to the through-hole surrounded by the groove.