Dot Photo Diode

Micro Dot Photodiode

The dot-diffusion photodiode (micro dot photodiode) is a photodiode with a completely new structure in which the light-receiving area is divided into microscopic dot-shaped diode junctions.

It is a proprietary technology that received the Excellent New Technology/New Product Award and the Excellent Technology Award of the Kyoto Technology Grand Prize, and the micro-diffusion photodiode technology has also been selected for a grant program of the New Technology Development Foundation. For details of the awards, see the Awards page.

Features

Proprietary structure that divides the light-receiving area into microscopic dot-shaped diode junctions
In a 1 mm square photodiode comparison, terminal capacitance is reduced from 20pF (conventional PD) to 4pF
Diode junction area of 0.002mm² (0.4μm² × 5K dots) versus 1mm² for a conventional PD

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 junction area of 0.002mm2 with 4pF terminal capacitance — Structural comparison of a conventional PD and the dot PD

Technology

Structure and Technology

In a 1 mm square photodiode comparison, the conventional PD has a full-surface diode junction (1mm²) with a terminal capacitance of 20pF, whereas the dot PD has a junction area of 0.002mm² (0.4μm² × 5K dots) and a terminal capacitance of 4pF. In addition to the low capacitance of the light-receiving area, a newly developed shield structure with dedicated shield wiring reduces spurious noise.

Cross-sectional drawing of the newly developed shield structure. Aluminum shield wiring is added to reduce spurious noise — Newly developed shield structure. Shield wiring is added to reduce spurious noise

Media

Media Coverage

The DOTPD technology was featured in the January 2021 issue (No. 165) of "Creative Kyoto M&T," a business information magazine of the Kyoto Industrial Support Center.

Pages of the January 2021 issue of Creative Kyoto M&T — Creative Kyoto M&T, January 2021 issue (Kyoto Industrial Support Center)

An introduction video of the DOTPD technology is also available.

Product Flyer (Performance Summary)

At the same sensitivity, more than 5 times the maximum speed (compared with our own products)
At the same speed, more than 5 times the sensitivity limit
S/N (signal-to-noise ratio) per bandwidth 2.2 times or more (our own measurements)
Parasitic capacitance of the photodetector element is 1/10 or less of conventional devices. An electromagnetic shield can also be built in
About 1/3 the capacitance even compared with PIN photodiode type ICs known for low capacitance (unshielded version)

Note: Figures are based on the product flyer "Shield-Integrated Low-Capacitance Dot Photo IC."

Product flyer for the shield-integrated low-capacitance dot photo IC — Product flyer (current document)

Applications

Typical Uses

Photodetector ICs requiring high sensitivity (adopted in various photo ICs as an ultra-low-capacitance photodiode)

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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