A photoelectric conversion element provided in a semiconductor layer having first and second surfaces includes a first region of a first conductivity type, a second region of a second conductivity type closer to the second surface than the first region and forming a p-n junction with the first region, a third region of the first conductivity type closer to the second surface than the second region, a fourth region of the second conductivity type closer to the second surface than the third region, a fifth region of the second conductivity type between the third fourth regions, and a sixth region of the second conductivity type surrounding a region where the first, second, third, and fifth regions are disposed in a plan view. The fifth region has an area smaller than that of the third region in the plan view, and overlaps with the first region in the plan view.

A photodetector and an integrated circuit with shortened response time requires a photodetector with an N-type semiconductor layer, a P-type semiconductor layer, and a light absorption layer sandwiched between the N-type semiconductor layer and the P-type semiconductor layer. The light absorption layer includes a layer strained in compression or in tension and a heterostructure which increases the mobility of charge carriers in the light absorption layer.

An avalanche photodiode includes a silicon layer on a substrate; a germanium layer on the silicon layer; a cathode and an anode on any of the silicon layer and the germanium layer; and a plurality of contacts on the germanium layer, in addition to the cathode and the anode. The silicon layer can include a highly doped region at each end, an intrinsic doped region in a middle, and an intermediately doped region between the highly doped region at each end and the intrinsic doped region, and the cathode and the anode are each at a respective a highly doped region at each end. The germanium layer can include a plurality of highly doped regions with each including one of the plurality of contacts.

An imaging device may include a plurality of single-photon avalanche diode (SPAD) pixels. The SPAD pixels may be overlapped by microlenses to direct light incident on the pixels onto photosensitive regions of the pixels and a containment grid with openings that surround each of the microlenses. During formation of the microlenses, the containment grid may prevent microlens material for adjacent SPAD pixels from merging. To ensure separation between the microlenses, the containment grid may be formed from material phobic to microlens material, or phobic material may be added over the containment grid material. Additionally, the containment grid may be formed from material that can absorb stray or off-angle light so that it does not reach the associated SPAD pixel, thereby reducing crosstalk during operation of the SPAD pixels.

Provided is a photodetector which can be manufactured in a standard process of a mass-produced CMOS foundry. The photodetector includes a silicon (Si) substrate; a lower clad layer; a core layer including a waveguide layer configured to guide signal light, and including a first Si slab doped with first conductive impurity ions and a second Si slab doped with second conductive impurity ions; a germanium (Ge) layer configured to absorb light and including a Ge region doped with the first conductive impurity ions; an upper clad layer; and electrodes respectively connected to the first and second Si slabs and the Ge region. A region of the core layer sandwiched between the first Si slab and the second Si slab operates as an amplification layer.

A photon detection device having a high light detection efficiency. The photon detection device includes a first light reception part which receives a gate signal and outputs a first signal; a second light reception part which receives a gate signal and outputs a second signal; and a determination part which determines whether or not a photon is received, on the basis of the first signal from the first light reception part and the second signal from the second light reception part. The photon is incident on the first light reception part among the first light reception part and the second light reception part, and the breakdown voltage of the second light reception part is higher than the breakdown voltage of the first light reception part.

An integrated circuit is formed in a semiconductor substrate. An array of single-photon-avalanche diodes is formed at a front side of the semiconductor substrate. The array includes first and second diodes that are adjacent to each other. A Bragg mirror is positioned between the first and second diodes. The Bragg mirror is configured to prevent a propagation of light between the first and second diodes.

Methods and devices for an avalanche photo-transistor. In one aspect, an avalanche photo-transistor includes a detection region configured to absorb light incident on a first surface of the detection region and generate one or more charge carriers in response, a first terminal in electrical contact with the detection region and configured to bias the detection region, an interim doping region, a second terminal in electrical contact with the interim doping region and configured to bias the interim doping region, a multiplication region configured to receive the one or more charge carriers flowing from the interim doping region and generate one or more additional charge carriers in response, a third terminal in electrical contact with the multiplication region and configured to bias the multiplication region, wherein the interim doping region is located in between the detection region and the multiplication region.

A photo-detecting apparatus is provided. The photo-detecting apparatus includes a carrier conducting layer having a first surface; an absorption region is doped with a first dopant having a first conductivity type and a first peak doping concentration, wherein the carrier conducting layer is doped with a second dopant having a second conductivity type and a second peak doping concentration, wherein the carrier conducting layer comprises a material different from a material of the absorption region, wherein the carrier conducting layer is in contact with the absorption region to form at least one heterointerface, wherein a ratio between the first peak doping concentration of the absorption region and the second peak doping concentration of the carrier conducting layer is equal to or greater than 10; and a first electrode and a second electrode both formed over the first surface of the carrier conducting layer.

Structures for an avalanche photodetector and methods of forming a structure for an avalanche photodetector. The structure includes a first semiconductor layer having a first portion and a second portion, and a second semiconductor layer stacked in a vertical direction with the first semiconductor layer. The first portion of the first semiconductor layer defines a multiplication region of the avalanche photodetector, and the second semiconductor layer defines an absorption region of the avalanche photodetector. The structure further includes a charge sheet in the second portion of the first semiconductor layer. The charge sheet has a thickness that varies with position in a horizontal plane, and the charge sheet is positioned in the vertical direction between the second semiconductor layer and the first portion of the first semiconductor layer.