Photosensitive devices and associated methods are provided. In one aspect, for example, a photosensitive imager device can include a semiconductor substrate having multiple doped regions forming at least one junction, a textured region coupled to the semiconductor substrate and positioned to interact with electromagnetic radiation, and an electrical transfer element coupled to the semiconductor substrate and operable to transfer an electrical signal from the at least one junction. In one aspect, the textured region is operable to facilitate generation of an electrical signal from the detection of infrared electromagnetic radiation. In another aspect, interacting with electromagnetic radiation further includes increasing the semiconductor substrate's effective absorption wavelength as compared to a semiconductor substrate lacking a textured region.

Photosensitive imaging devices and associated methods

In one aspect, the present invention provides a silicon photodetector having a surface layer that is doped with sulfur inclusions with an average concentration in a range of about 0.5 atom percent to about 1.5 atom percent. The surface layer forms a diode junction with an underlying portion of the substrate. A plurality of electrical contacts allow application of a reverse bias voltage to the junction in order to facilitate generation of an electrical signal, e.g., a photocurrent, in response to irradiation of the surface layer. The photodetector exhibits a responsivity greater than about 1 A/W for incident wavelengths in a range of about 250 nm to about 1050 nm, and a responsivity greater than about 0.1 A/W for longer wavelengths, e.g., up to about 3.5 microns.

Silicon-based visible and near-infrared optoelectric devices

Increasing the modulation speed of semiconductor lasers has attracted much attention from the viewpoint of both physics and the applications of lasers. Here we propose a membrane distributed reflector laser on a low-refractive-index and high-thermal-conductivity silicon carbide substrate that overcomes the modulation bandwidth limit. The laser features a high modulation efficiency because of its large optical confinement in the active region and small differential gain reduction at a high injection current density. We achieve a 42 GHz relaxation oscillation frequency by using a laser with a 50-μm-long active region. The cavity, designed to have a short photon lifetime, suppresses the damping effect while keeping the threshold carrier density low, resulting in a 60 GHz intrinsic 3 dB bandwidth (f3dB). By employing the photon–photon resonance at 95 GHz due to optical feedback from an integrated output waveguide, we achieve an f3dB of 108 GHz and demonstrate 256 Gbit s−1 four-level pulse-amplitude modulations with a 475 fJ bit−1 energy cost of the direct-current electrical input. Directly modulated membrane distributed reflector lasers are fabricated on a silicon carbide platform. The 3 dB bandwidth, four-level pulse-amplitude modulation speed and operating energy for transmitting one bit are 108 GHz, 256 Gbit s−1 and 475 fJ, respectively.

Directly modulated membrane lasers with 108 GHz bandwidth on a high-thermal-conductivity silicon carbide substrate

The present invention generally provides semiconductor substrates having submicron-sized surface features generated by irradiating the surface with ultra short laser pulses. In one aspect, a method of processing a semiconductor substrate is disclosed that includes placing at least a portion of a surface of the substrate in contact with a fluid, and exposing that surface portion to one or more femtosecond pulses so as to modify the topography of that portion. The modification can include, e.g., generating a plurality of submicron-sized spikes in an upper layer of the surface.

Femtosecond Laser-Induced Formation Of Submicrometer Spikes On A Semiconductor Substrate

To reduce the ever-increasing energy consumption in datacenters, one of the effective approaches is to increase the ambient temperature, thus lowering the energy consumed in the cooling systems. However, this entails more stringent requirements for the reliability and durability of the optoelectronic components. Herein, we fabricate and demonstrate silicon-polymer hybrid modulators which support ultra-fast single-lane data rates up to 200 gigabits per second, and meanwhile feature excellent reliability with an exceptional signal fidelity retained at extremely-high ambient temperatures up to 110 °C and even after long-term exposure to high temperatures. This is achieved by taking advantage of the high electro-optic (EO) activities (in-device n3r33 = 1021 pm V−1), low dielectric constant, low propagation loss (α, 0.22 dB mm−1), and ultra-high glass transition temperature (Tg, 172 °C) of the developed side-chain EO polymers. The presented modulator simultaneously fulfils the requirements of bandwidth, EO efficiency, and thermal stability for EO modulators. It could provide ultra-fast and reliable interconnects for energy-hungry and harsh-environment applications such as datacentres, 5G/B5G, autonomous driving, and aviation systems, effectively addressing the energy consumption issue for the next-generation optical communication. Information and communication datacentres require a large amount of energy for their cooling systems, which could be decreased by working at higher temperatures. Here, the authors introduce a silicon-polymer hybrid modulator that maintains high data rates for long periods at high temperatures that could be used under such conditions, to reduce energy consumption.

/pdf/high-temperature-resistant-silicon-polymer-hybrid-modulator-cerdi2mrje.pdf

High-temperature-resistant silicon-polymer hybrid modulator operating at up to 200 Gbit s-1 for energy-efficient datacentres and harsh-environment applications.

In an optical semiconductor device that emits or receives light substantially perpendicularly to or in parallel to an active surface formed on a semiconductor substrate, the optical semiconductor device, an electrode (20) that is formed on the active surface side and connected to the active surface is stepped or tapered at an end of the electrode. The electrode of the optical semiconductor device is formed of three layers including an adhesive layer, a diffusion prevention layer, and an Au layer, and the stepped configuration or the taped configuration is formed by a difference of the thickness of the Au layer (20a) or the thickness of the adhesive layer/diffusion prevention layer/Au layer.

Optical semiconductor device

PROBLEM TO BE SOLVED: To provide a semiconductor device having a structure such that a polyimide resin is arranged below a pad electrode to reduce a parasitic capacitance, thereby solving the following problem that an electrode step disappears in a step difference of a polyimide surface, and it becomes hard to reduce the parasitic capacitance through the increase of the step difference.SOLUTION: In a semiconductor optical device, a compound semiconductor layer is laminated which includes an etching stop layer 32 and an active layer 36 and is laminated on a semiconductor substrate 2. A ridge 20 and a lower part 42 on both sides of the ridge are formed by etching to the active layer 36. A part positioned under the pad electrode 14 among the lower parts 42 is etched to the etching stop layer 32, thereby forming a recess 46. The polyimide resin layer 22 has, below the pad electrode 14, a thickness formed by the depth of the lower part 42, the height of a terrace part 48 and the depth of the recess 46. The parasitic capacitance is reduced by increasing the depth of the recess 46.

Semiconductor device and method of manufacturing the same

A 1.3- μ m directly modulated distributed feedback laser was newly developed by adopting an asymmetric corrugation pitch modulated grating structure and an InGaAlAs multiquantum well active layer with both a high optical confinement factor and a high differential gain. A low threshold current and a large saturation current in light-current characteristics at high temperature were obtained and a high 3-dB bandwidth and a high relaxation oscillation frequency in electro-optical characteristics were also achieved over a wide temperature range. As a result, clear back-to-back eye openings were achieved for 26-Gbaud PAM4 (53-Gb/s) operation from 25 to 95 °C with large outer extinction ratio and sufficiently small transmission dispersion eye closure quaternary. Furthermore, 53-Gbaud PAM4 (106-Gb/s) operation from 25 to 80 °C was successfully demonstrated for both back-to-back and after 10-km single mode fiber transmission. These excellent characteristics make our DFB laser a promising cost-effective and compact transceiver with low power consumption for next-generation 400GbE applications.

Wide-Temperature-Range (25–80 °C) 53-Gbaud PAM4 (106-Gb/s) Operation of 1.3- μ m Directly Modulated DFB Lasers for 10-km Transmission

We developed a high-bandwidth 1.3- μ m uncooled electro-absorption modulator-integrated distributed-feedback laser and demonstrated uncooled 53-GBd four-level pulse amplitude modulation (PAM4) operation with low drive voltage for the first time. Specifically, 53-GBd PAM4 operation with the drive voltage of 0.9 V pp from 20 to 85 °C was achieved. The extinction ratio of more than 4.9 dB and transmission dispersion eye closure quaternary of less than 2.3 dB were obtained from 20 to 85 °C in the 53 GBd-PAM4 operation.

Uncooled Operation of 53-GBd PAM4 (106-Gb/s) EA/DFB Lasers With Extremely Low Drive Voltage With 0.9 V pp

Uncooled 53-Gbaud PAM4 operation of $1.3-\mu \text{m}$ electro-absorption modulator integrated DFB laser was demonstrated with 0.9 Vpp for the first time. We obtained extinction ratio of more than 4.9 dB and TDECQ of less than 2.3 dB from 20 to 85°C.

Shigenori Hayakawa

Papers

Optical semiconductor device

Semiconductor device and method of manufacturing the same

Wide-Temperature-Range (25–80 °C) 53-Gbaud PAM4 (106-Gb/s) Operation of 1.3- μ m Directly Modulated DFB Lasers for 10-km Transmission

Uncooled Operation of 53-GBd PAM4 (106-Gb/s) EA/DFB Lasers With Extremely Low Drive Voltage With 0.9 V pp

Uncooled Operation of 53-Gbaud PAM4 (106-Gb/s) EA/DFB Lasers with Extremely Low Drive Voltage with 0.9 Vpp