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.

A Ge-on-Si photodetector constructed without doping or contacting Germanium by metal is described. Despite the simplified fabrication process, the device has responsivity of 1.24 A/W, corresponding to 99.2% quantum efficiency. Dark current is 40 nA at 4 V reverse bias. 3-dB bandwidth is 30 GHz.

Structures and techniques introduced here enable the design and fabrication of photodetectors (PDs) and/or other electronic circuits using typical semiconductor device manufacturing technologies meanwhile reducing the adverse impacts on PDs' performance. Examples of the various structures and techniques introduced here include, but not limited to, a pre-PD homogeneous wafer bonding technique, a pre-PD heterogeneous wafer bonding technique, a post-PD wafer bonding technique, their combinations, and a number of mirror equipped PD structures. With the introduced structures and techniques, it is possible to implement PDs using typical direct growth material epitaxy technology while reducing the adverse impact of the defect layer at the material interface caused by lattice mismatch.

A SPAD including, in a substrate of a first conductivity type: a first region of the second conductivity type extending from the upper surface of the substrate; a second region of the first type of greater doping level than the substrate, extending from the lower surface of the first region, having a surface area smaller than that of the first region and being located opposite a central portion of the first region; a third region of the first type of greater doping level than the substrate extending from the upper surface of the substrate, laterally surrounding the first region; and a fourth buried region of the first type of greater doping level than the substrate, forming a peripheral ring connecting the second region to the third region.

A semiconductor light detection element includes a plurality of avalanche photodiodes operating in Geiger mode and formed in a semiconductor substrate, quenching resistors connected in series to the respective avalanche photodiodes and arranged on a first principal surface side of the semiconductor substrate, and a plurality of through-hole electrodes electrically connected to the quenching resistors and formed so as to penetrate the semiconductor substrate from the first principal surface side to a second principal surface side. A mounting substrate includes a plurality of electrodes arranged corresponding to the respective through-hole electrodes on a third principal surface side. The through-hole electrodes and the electrodes are electrically connected through bump electrodes, and a side surface of the semiconductor substrate and a side surface of a glass substrate are flush with each other.

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.

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.

The present disclosure relates to a semiconductor photomultiplier comprising a substrate; an array of photosensitive cells formed on the substrate that are operably coupled between an anode and a cathode. A set of primary bus lines are provided each being associated with a corresponding set of photosensitive cells. A secondary bus line is coupled to the set of primary bus lines. An electrical conductor is provided having a plurality of connection sites coupled to respective connection locations on the secondary bus line for providing conduction paths which have lower impedance than the secondary bus line.

A delay circuit is provided. The delay circuit includes a first regulator and a second regulator, each of which is independently selectable based on a selection signal applied to a selection terminal of the delay circuit. Furthermore, the delay circuit is configurable in one of two distinct delay resolution regimes, each corresponding to only one edge an input signal being actively delayed by the delay circuit when one of the first regulator and the second regulator is enabled and the other one of the first regulator and the second regulator is turned off.

The present disclosure provides an avalanche photodetector and a preparation method therefor. The avalanche photodetector comprises: a substrate, the surface of which comprises a first semiconductor layer; and a second semiconductor layer located on the substrate, wherein the first semiconductor layer comprises a first P-type doped region, a second P-type doped region, a third N-type doped region, a first intrinsic region, a third P-type doped region, a second intrinsic region, a second N-type doped region and a first N-type doped region which are sequentially arranged in a first direction, the dopant concentrations of the first to third P-type doped regions are sequentially decreased, the dopant concentrations of the first to third N-type doped regions are sequentially decreased, and the first direction is an electron flow direction; the second semiconductor layer sequentially covers part of the second P-type doped region, the third N-type doped region, the first intrinsic region and the third P-type doped region in the first direction; the first N-type doped region is connected to a first electrode; the third P-type doped region is connected to a second electrode; and the first N-type doped region is connected to a third electrode.