Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as pillars and/or holes, effectively increase the effective absorption length resulting in a greater 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.

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as pillars and/or holes, effectively increase the effective absorption length resulting in a greater 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.

A method of packaging the silicon photonics wafer for fabricating custom optical-electrical modules includes fabricating a wafer with multiple dies of silicon photonics circuits based on custom design and conducting electrical and optical tests of the silicon photonics circuits in wafer level. The method further includes preparing the wafer for next point of use. Additionally, the method includes performing post-wafer processing on the wafer received at the next point of use. The method further includes conducting post-process electrical tests of the silicon photonics circuits in wafer level. Furthermore, the method includes preparing the wafer with known-good-dies or a known-good-wafer identified for custom use. Moreover, the method includes performing custom process on the know good dies.

An apparatus includes a first semiconductor layer including a first bandgap; and a second semiconductor layer of a first polarity including a second bandgap smaller than the first bandgap and formed over the first semiconductor layer. The first semiconductor layer includes a first conductive region of the first polarity, a second conductive region of a second polarity, and a non-conductive region between the first conductive region and the second conductive region, and the second semiconductor layer is in contact with the first conductive region and the non-conductive region.

Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.

A method of generating a germanium structure includes performing an epitaxial depositing process on an assembly of a silicon substrate and an oxide layer, wherein one or more trenches in the oxide layer expose surface portions of the silicon substrate. The epitaxial depositing process includes depositing germanium onto the assembly during a first phase, performing an etch process during a second phase following the first phase in order to remove germanium from the oxide layer, and repeating the first and second phases. A germanium crystal is grown in the trench or trenches. An optical device includes a light-incidence surface formed by a raw textured surface of a germanium structure obtained by an epitaxial depositing process without processing the surface of the germanium structure after the epitaxial process.

Light detecting structures comprising germanium (Ge) photodiodes formed in a device layer of a germanium on-insulator (GeOI) wafer, focal planes arrays based on such Ge photodiodes (PDs) and methods for fabricating such Ge photodiodes and focal plane arrays (FPAs). An FPA includes a Ge-on-GeOI PD array bonded to a ROIC where the handle layer of the GeOI layer is removed. The GeOI insulator properties and thickness can be designed to improve light coupling into the PDs.

A problem to be solved is to make plural Ge PDs uniform in sensitivity by heating the Ge PDs with heaters based on photocurrent measurements taken by a current monitor, and thereby curb deterioration in a common-mode rejection ratio. A photodetector according to the present invention is a germanium photodetector (Ge PD) that uses germanium or a germanium compound in a light absorption layer, the photodetector including two or more Ge PDs placed to receive an input differential signal; a current monitor adapted to measure photocurrents of the two or more Ge PDs; resistors adapted to heat the respective Ge PDs; voltage sources connected to the respective resistors and capable of controlling voltage values independently of each other, wherein the voltage sources are connected with the current monitor, and the voltage sources manipulate voltages applied to the heaters such that current values output by the two or more Ge PDs will match each other.

A photodetector includes a photodetecting region in a semiconductor substrate, and a reflector extending at least partially along a sidewall of the photodetecting region in the semiconductor substrate. The reflector includes an air gap defined in the semiconductor substrate. The reflector allows use of thinner germanium for the photodetecting region. The air gap may have a variety of internal features to direct electromagnetic radiation towards the photodetecting region.

Structures for a photodetector and methods of fabricating a structure for a photodetector. A photodetector may have a light-absorbing layer comprised of germanium. A waveguide core may be coupled to the light-absorbing layer. The waveguide core may be comprised of a dielectric material, such as silicon nitride. Another waveguide core, which may be comprised of a different material such as single-crystal silicon, may be coupled to the light-absorbing layer.