Technology & R&D

Technology

Fabless Development

Fabless Development System

Microsignal is a fabless semiconductor manufacturer with no factories of its own, specializing in the design and development of photodetector ICs. Making the most of the advantages of outsourcing, we use major semiconductor manufacturers in Japan and overseas as foundries, selecting the manufacturing process best suited to each application.

Our proprietary management methods also make small-volume production possible, which in turn makes it easy for us to support research and development. It is a system that enables what larger manufacturers cannot offer: full-custom photodetector ICs from small volumes.

Using monolithic photo IC technology that combines high speed and high sensitivity, we develop high-performance yet affordable devices. In the field of short distance optical fiber communication, we supply transmitter and receiver devices with world-leading performance to communications equipment manufacturers.

Main Semiconductor Processes
Process	Feature size
CMOS	From 0.15μm
BiCMOS	From 0.25μm
Bipolar	From 0.25μm
Mixed Signal	From 0.15μm

Note: Expressions such as "world-leading" are based on the wording of our current website and will be finalized after verification against supporting data.

Core Technology

Proprietary Technology: Dot Photodiode

Our proprietary photodiode structure, the "dot-diffusion photodiode," is a technology that gives the photodetector element far lower capacitance than other companies' products, achieving higher sensitivity and higher S/N. The basic patents were obtained in the United States in 2017 and in Japan in 2018.

Combining this structure with our shield structure, we have confirmed performance of more than 5 times the maximum speed at the same sensitivity and an S/N ratio 2.2 times or more (both from our own measurements).

Structural comparison of a conventional PD and the dot PD. In a 1 mm square photodiode, the conventional PD has a diode junction across the entire surface with 20pF terminal capacitance, while the dot PD has a diode area of 0.002 square millimeters with 4pF terminal capacitance — Dot PD structure: While a conventional PD uses the entire light-receiving area as the diode junction, the dot PD divides the junction into microscopic dots. In a comparison of 1 mm square photodiodes, terminal capacitance drops sharply from 20pF for the conventional PD to 4pF for the dot PD (our own data).

3D structural CG of the dot photodiode. Wiring runs above the silicon substrate, with microscopic diode junctions arranged regularly beneath it — 3D structural CG of the dot PD: The microscopic diode junctions (dots) are arranged regularly beneath the wiring, and most of the light-receiving area remains bare silicon substrate.

Cross-sectional drawing of the newly developed shield structure. Aluminum shield wiring and cathode wiring are placed on the SiO2 film, and the N diffusion of the P substrate is grounded — Newly developed shield structure: Aluminum shield wiring is added to reduce spurious noise. It eliminates the need for an external shield and produces photodetector ICs that are resistant to external electromagnetic noise.

Note: The performance figures (maximum speed and S/N ratio) are based on our own measurements (as stated in the product flyer).

Spectral Sensitivity

Sensitivity Wavelength Range

We build photodetector ICs across a wide wavelength range, from visible light to near infrared. The wavelength range we can support depends on the product and process, so please consult us individually about specific requirements.

Spectral Sensitivity Range 400–1600 nm

From visible light to near infrared. Ranges shown are samples.

Development & Evaluation

Development and Evaluation Systems

We handle everything from LSI design and development to measurement and evaluation of the fabricated LSIs. For design, we use circuit simulation (CADENCE, HSPICE, SPECTRE, PSPICE) and the CADENCE LSI development system (circuit verification, mask layout and design rule checking).

The main equipment of our measurement, evaluation and optical instrumentation systems includes oscilloscopes, network analyzers, bit error rate testers, optical spectrum analyzers, laser light sources, a laser trimmer, probers, wire bonders, environmental test chambers, E/O converters, O/E converters and optical benches.

Optical measurement and evaluation on the optical bench

For anything optical, talk to us first.

You do not need finalized specifications. We will work with you on the design of the entire photodetection system.

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