0.18 & 0.35μm UV photodiodes offer high quantum efficiency

The diodes offer a cost-effective open door to a wide variety of wearable, medical and industrial applications that previously required dedicated processes or discrete diodes. X-FAB’s UV sensors are suited for applications such as smart watches and smartphones that detect UV light. They also are valuable in the industrial sector for water purification and disinfection systems or for flame detection and other applications, and in the medical sector for light therapies or the detection of blood sugar in diabetes monitoring.

In X-FAB’s 0.35μm foundry process, the quantum efficiency (measurement of a device's electrical sensitivity to light) especially in the UV-A and UV-B wavelength range is more than 70%, and in X-FAB’s 0.18μm technology it is more than 50%. Such levels previously have been reported only for photodiodes manufactured with special processes that use back-side illumination, or for discrete UV photodiodes.

Even though they are optimised for UV light, the diodes also perform well in the visible and infrared light spectra, achieving a quantum efficiency rating higher than 70% for visible light. They support applications that require a broad wavelength range from UV to IR light, such as spectroscopy.

Designers are able to use just one photodiode structure for different wavelengths, enabling a cost reduction. A low dark current results in a good SNR, potentially reducing the size of the photodiode, further reducing costs. As part of X-FAB’s standard CMOS process offerings, the integrated UV photodiodes allow customers to design integrated optoelectronic systems on a single chip instead of the two-chip solution previously required.

“This expansion of X-FAB’s family of successful optoelectronic sensors already manufactured in high volumes for ambient light and proximity sensing allows our customers to venture into entirely new application areas,” commented Detlef Sommer, Business Line Manager, Optoelectronics, X-FAB. “For example, the enhanced models of the XH018 UV diodes enable designers without special optical knowledge to design integrated optoelectronic systems.”

X-FAB will offer a free webinar covering the UV sensors on Tuesday 5^th May 2015 for the North and South American audience, and on Wednesday 6^th May for designers in EMEA. To register for the webinars, click here, for America, and click here, for EMEA. Interested parties also can visit X-FAB in Hall 12, Booth 582 at the Sensor + Test exhibition in Nuremberg, Germany on 19^th to 21^st May 2015. Dr. Christoph Henkel, one of the UV photodiode developers, also will present at the associated Sensor congress.

Both UV sensors and comprehensive process design kits for 0.35 and 0.18μm technologies are available for immediate use. For XH018, a special dedicated VERILOG-A behavioral photodiode model for each photodiode will be provided by the end of June 2015, allowing designers to apply their customary electrical design flow to the complicated physical process of light sensing.