Featured Research

from universities, journals, and other organizations

New etching method to produce 3-D microstructures in silicon for processing of light signals in telecommunications

Date:
October 5, 2012
Source:
Karlsruhe Institute of Technology
Summary:
In modern telecommunications, light carries digital information over kilometers within seconds. Adapted optical materials control the light signals. Researchers now have a new method to produce photonic crystals. Their optical properties are adjusted by structures of micrometer size. The method is rapid, cheap, and simple and partly uses the self-organization principle.

Deep below the silicon surface, the SPRIE method produces regular structures in the micrometer range that refract light.
Credit: KIT/CFN

In modern telecommunications, light carries digital information over kilometers within seconds. Adapted optical materials control the light signals. In the journal Advanced Functional Materials, researchers from Berlin, Louvain, and from Karlsruhe Institute of Technology present a method to produce photonic crystals. Their optical properties are adjusted by structures of micrometer size. The method is rapid, cheap, and simple and partly uses the self-organization principle.

"Optical properties of materials can be influenced decisively by specific structurization," explains Andreas Frölich from Karlsruhe Institute of Technology. Silicon is used in components, e.g. filters or deflectors, for telecommunications. So far, however, all these components have been flat, i.e. two-dimensional. Entirely novel concepts might be feasible using three-dimensional components. The expenditure required to structure the silicon is very high. The structure has to be very regular in all three spatial directions and details are to have the size of about one micrometer, which corresponds to one hundredth of the thickness of a hair.

"Our new SPRIE fabrication methods uses established technologies, such as etching and innovative methods like self-organization and combines them in a very creative manner," says Martin Wegener, Professor of the Institute of Applied Physics and Institute of Nano-technology of KIT and coordinator of the DFG Center for Functional Nanostructures (CFN). The SPRIE method is applied to structure silicon on large areas in a simple and three-dimensional manner. First, a solution with micrometer-sized spheres of polystyrene is applied to the silicon surface. After drying, these spheres automati-cally form in a dense monolayer on the silicon. Upon metal coating and the removal of the spheres, a honeycomb etching mask remains on the silicon surface.

"This etching mask is our two-dimensional template for the construction of the three-dimensional structure," says Frölich. The free areas are removed by etching with a reactive plasma gas. An electric field is applied to make the gas particles etch into the depth only or ho-mogeneously in all directions." In addition, we can specifically passivate the walls of the hole, which means that it is protected from further etching by a polymer layer."

Repeated etching and passivation makes the holes of the etching mask grow into the depth. With up to 10 micrometers, their depth exceeds their width by a factor of more than 10. The process steps and the electric field are adjusted precisely to control the structure of the walls. Instead of a simple hole with vertical smooth walls, every etching step produces a spherical depression with a curved surface. This curvature is the basis for the regular repeating structures of novel waveguides. "Optical telecommunication takes place at a wavelength of 1.5 µm. With our etching method, we produce a cor-rugated structure in the micrometer range along the wall." The field at closely adjacent and very deep, structured holes acts like a regular crystal that refracts in the desired manner.

The SPRIE (Sequential Passivation and Reactive Ion Etching) method can produce a three-dimensional photonic crystal within a few minutes, as it is based on conventional industrial processes. In principle, a three-dimensional structure can be generated in silicon using a freely choosable mask. This opens up new possibilities for meeting the requirements made on optical components in telecommunications.

Different designs of photonic crystals are available. Some are applied as waveguides with very small curvature radii and small losses or as extremely small-band optical filters and multiplexers. In few decades, computers working with light instead of electricity might be feasible. Apart from KIT, the Belgian Université catholique de Louvain and Humboldt University, Berlin, were involved in the development.


Story Source:

The above story is based on materials provided by Karlsruhe Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Karlsruhe Institute of Technology. "New etching method to produce 3-D microstructures in silicon for processing of light signals in telecommunications." ScienceDaily. ScienceDaily, 5 October 2012. <www.sciencedaily.com/releases/2012/10/121005103239.htm>.
Karlsruhe Institute of Technology. (2012, October 5). New etching method to produce 3-D microstructures in silicon for processing of light signals in telecommunications. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2012/10/121005103239.htm
Karlsruhe Institute of Technology. "New etching method to produce 3-D microstructures in silicon for processing of light signals in telecommunications." ScienceDaily. www.sciencedaily.com/releases/2012/10/121005103239.htm (accessed April 19, 2014).

Share This



More Matter & Energy News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) — After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Horseless Carriage Introduced at NY Auto Show

Horseless Carriage Introduced at NY Auto Show

AP (Apr. 17, 2014) — An electric car that proponents hope will replace horse-drawn carriages in New York City has also been revealed at the auto show. (Apr. 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) — It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) — German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
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:
from the past week

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