Intel Corporation

Yimin Kang

Yun-Chung Na

Han-Din Liu

Yuval Saado

Shu-Lu Chen

Ansheng Liu

Alexandre Pauchard

Gadi Sarid

Zhihong Connie Huang

An Si/Ge SACM avalanche photodiodes (APD) having low breakdown voltage characteristics includes an absorption region and a multiplication region having various layers of particular thicknesses and doping concentrations. An optical waveguide can guide infrared and/or optical signals or energy into the absorption region. The resulting photo-generated carriers are swept into the i-Si layer and/or multiplication region for avalanche multiplication. The APD has a breakdown bias voltage of well less than 12 V and an operating bandwidth of greater than 10 GHz, and is therefore suitable for use in consumer electronic devices, high speed communication networks, and the like.

Avalanche photodiode with low breakdown voltage

A low voltage APD is disposed at an end of a waveguide extending laterally within a silicon device layer of a PIC chip. The APD is disposed over an inverted re-entrant mirror co-located at the end of the waveguide to couple light by internal reflection from the waveguide to an under side of the APD. In exemplary embodiments, a 45&#xb0;-55&#xb0; facet is formed in the silicon device layer by crystallographic etch. In embodiments, the APD includes a silicon multiplication layer, a germanium absorption layer over the multiplication layer, and a plurality of ohmic contacts disposed over the absorption layer. An overlying optically reflective metal film interconnects the plurality of ohmic contacts and returns light transmitted around the ohmic contacts to the absorption layer for greater detector responsivity.

Low voltage avalanche photodiode with re-entrant mirror for silicon based photonic integrated circuits

An Si/Ge SACM avalanche photo-diodes (APD) having low breakdown voltage characteristics includes an absorption region and a multiplication region having various layers of particular thicknesses and doping concentrations. An optical waveguide can guide infrared and/or optical signals or energy into the absorption region. The resulting photo-generated carriers are swept into the i-Si layer and/or multiplication region for avalanche multiplication. The APD has a breakdown bias voltage of well less than 12 V and an operating bandwidth of greater than 10 GHz, and is therefore suitable for use in consumer electronic devices, high speed communication networks, and the like.

A low voltage photodetector structure including a semiconductor device layer, which may be Ge, is disposed over a substrate semiconductor, which may be Si, for example within a portion of a waveguide extending laterally within a photonic integrated circuit (PIC) chip. In exemplary embodiments where the device layer is formed over an insulator layer, the insulator layer is removed to expose a surface of the semiconductor device layer and a passivation material formed as a replacement for the insulator layer within high field regions. In further embodiments, controlled avalanche gain is achieved by spacing electrodes in a metal-semiconductor-metal (MSM) architecture, or complementary doped regions in a p-i-n architecture, to provide a field strength sufficient for impact ionization over a distance not significantly more than an order of magnitude greater than the distance that a carrier must travel so as to acquire sufficient energy for impact ionization.

Low voltage photodetectors

A photonic integrated circuit (I/C) includes a focusing sidewall or in-plane surface that redirects and focuses light from a waveguide to a photodetector structure. The focusing includes redirecting an optical signal to a width smaller than a width of the waveguide. The focusing of the light allows the photodetector structure to be outside a waveguide defined by parallel oxide structures. With the photodetector structure outside the waveguide, the contacts can be placed closer together, which reduces contact resistance.

Re-entrant mirror photodetector with waveguide mode focusing

Devices comprised of end-on waveguide-coupled photodetectors are described. In embodiments of the invention, the photodetectors are avalanche photodiodes coupled end-on to a waveguide. The waveguide includes an insulating trench proximate to the coupled photodetector. In embodiments of the invention, the avalanche photodiodes are silicon/germanium avalanche photodiodes.

Waveguide avalanche photodetectors

Photodetectors operable to achieve multiplication of photogenerated carriers at ultralow voltages. Embodiments include a first p-i-n semiconductor junction combined with a second p-i-n semiconductor junction to form a monolithic photodetector having at least three terminals. The two p-i-n structures may share either the p-type region or the n-type region as a first terminal. Regions of the two p-i-n structures doped complementary to that of the shared terminal form second and third terminals so that the first and second p-i-n structures are operable in parallel. A multiplication region of the first p-i-n structure is to multiply charge carriers photogenerated within an absorption region of the second p-i-n structure with voltage drops between the shared first terminal and each of the second and third terminals being noncumulative.

Monolithic three terminal photodetector

An avalanche photodetector is disclosed. An apparatus according to aspects of the present invention includes a mesa structure defined in a first type of semiconductor. The first type of semiconductor material includes an absorption region optically coupled to receive and absorb an optical beam. The apparatus also includes a planar region proximate to and separate from the mesa structure and defined in a second type of semiconductor material. The planar region includes a multiplication region including a p doped region adjoining an n doped region to create a high electric field in the multiplication region. The high electric field is to multiply charge carriers photo-generated in response to the absorption of the optical beam received in the mesa structure.

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San Jose, CA, United States of America

Yimin Kang