Featured Research

from universities, journals, and other organizations

UV-transparent coating for image sensors

Date:
February 24, 2011
Source:
Fraunhofer-Gesellschaft
Summary:
Image sensors as used in cell phones are partially color-blind. This is because of their coating, which prevents UV light from passing through. CMOS chips have as a result not been suitable for spectroscopy up to now. A new production process makes the coating transparent -- and the sensors suitable for special applications.

CMOS image sensors can now be covered with a transparent protective coating that is permeable to light in the UV and blue spectral range.
Credit: Copyright Fraunhofer IMS

They have been used as standard in multimedia electronics for a long time, and now they are making rapid inroads in high performance applications: CMOS image sensors are no longer only used in cell phones and digital cameras. The automotive industry, for instance, has discovered the potential of optical semiconductor chips and is increasingly using them in driver assistance systems -- from parking aids and road lane detection to blind-spot warning devices. In special applications, however, the sensors that convert light into electrical signals have to cope with diffi cult operating conditions, for example high temperatures and moisture.

Related Articles


For this reason, CMOS devices are covered with a silicon nitride coating. This chemical compound forms hard layers which protect the sensor from mechanical influences and the penetration of moisture and other impurities. The protective coating is applied to the sensor in the final stage of CMOS semiconductor production. The process is called passivation, and is an industry requirement. Unfortunately, up to now this passivation has entailed a problem: the silicon nitride coating limits the range of optical applications because it is impermeable to light in the UV and blue spectral range. CMOS sensors for high-performance applications, used in special cameras are therefore partially color-blind.

Scientists at the Fraunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg have found a solution to this problem: "We've developed a new process step," says Werner Brockherde, head of department at Fraunhofer IMS, "that allows us to produce a protective coating with the same properties but which is permeable to blue and UV light." The trick is to increase the proportion of nitrogen in the coating. "This reduces the absorption of shortwave light," explains Brockherde.

In simplified terms, the new coating material will absorbless light of an energy higher than blue light, which means the sensor becomes more sensitive at the blue and UV range. "This makes CMOS image sensors suitable for use in wavelength ranges down to 200 nanometers," states Brockherde. "With standard passivation the limit was about 450 nanometers." To change the structure of the silicon nitride for the coating, the Fraunhofer research scientists had to fine-tune the deposition parameters such as pressure and temperature.

With this process development the experts have expanded the range of applications for CMOS image technology. This could revolutionize UV spectroscopic methods, which are used in laboratories around the world, significantly improving their accuracy. Likewise, CMOS image sensors stand to take up a new role in professional microscopy, e.g. in fluorescence microscopes, providing scientists with images of even greater detail.


Story Source:

The above story is based on materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.


Cite This Page:

Fraunhofer-Gesellschaft. "UV-transparent coating for image sensors." ScienceDaily. ScienceDaily, 24 February 2011. <www.sciencedaily.com/releases/2011/02/110223122417.htm>.
Fraunhofer-Gesellschaft. (2011, February 24). UV-transparent coating for image sensors. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2011/02/110223122417.htm
Fraunhofer-Gesellschaft. "UV-transparent coating for image sensors." ScienceDaily. www.sciencedaily.com/releases/2011/02/110223122417.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins