Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New industrial research technique for analyzing gallium nitride on the nanometer scale

07.11.2014

Gallium nitride is difficult to produce and difficult to handle – and the key to the development of blue LEDs, which won this year’s Nobel Prize in Physics.

The award went to three Japanese researchers who were the first to produce high-quality gallium nitride (GaN) layers and put them into series production back in 1993. Now, researchers and engineers around the world are working on analyzing and optimizing this material.


Near-field microscope with a fragment of a gallium nitride wafer.

Picture Source: Fraunhofer ILT, Aachen, Germany.

The Fraunhofer Institute for Laser Technology ILT has worked closely with RWTH Aachen University’s I. Institute of Physics (IA) to develop an analysis technology that, for the very first time, allows the structural and electronic properties of GaN and GaN composites to be studied optically on the nanometer level.

Industry’s need for mass-producible LEDs is growing, whether for smartphone, computer and TV screens or for the lighting sector. One important reason is that LEDs use many times less energy than incandescent bulbs, halogen bulbs or even energy-saving bulbs. The development of the blue LED was the last step in creating white LED light – a particularly pleasant light that significantly boosts user acceptance of the technology, for instance in home applications. Developing increasingly efficient components will rely on a quick and cost-effective analysis technique.

Optical analysis on the nanometer scale

The resolution of conventional optical microscopes reaches its physical limits when confronted with objects on the nanometer scale. Because of the light source employed, tiny structures in the nanometer range – such as those you find in modern semiconductor components – cannot be brought into focus. This rules out optical analysis techniques. Near-field microscopy circumvents this fundamental limitation and penetrates the nanometer domain to provide an optical view. This places extremely high demands on the light source used.

Aachen laser system for using near-field microscopy techniques on gallium nitride

In collaboration with fellow researchers from the Chair for Experimental Physics at RWTH Aachen University, scientists from Fraunhofer ILT have spent the past few years developing an innovative, broadband tunable laser system that is geared toward the particular requirements of semiconductor analysis. Wavelength can be adjusted to the material under inspection, which enables the new system to investigate a wide range of materials. 

In contrast to the solutions available on the market to date and those employed in research and development, the new system from Aachen provides the means for much faster spectroscopic analyses. It has also opened up access to material systems that were beyond the capacities of previous systems. This includes GaN and GaN composites.

Using the new analysis system, last year the researchers in Aachen were able to obtain an optical 2D image showing tensions in the crystal structure of undoped GaN wafers for the very first time. Computer simulations helped quantify the exact extent of the tension. Recently the technique was also applied to a variety of doped GaN layers within complex structures. It’s the first time an optical technique has been available to study the structural and electronic properties of GaN and GaN composites on the nanometer scale.

Cost-effective, precise and non-destructive

Near-field microscopy offers cost and quality benefits over standard analysis techniques. The structural properties of thin GaN layers are currently studied using transmission electron microscopy; however, the costs incurred are extremely high, due in part to the laborious sample preparation process. Near-field analysis can usually be conducted without any preparation. Another benefit concerns secondary ion mass spectrometry, which is used to study the electronic properties.

Although this technique can be used to determine electronic properties along an axis at the nanometer level, it isn’t yet possible to laterally ascertain the concentration of doping atoms at a comparable resolution. The technique also damages the samples. In contrast, near-field microscopy offers nanometer-scale resolution in all dimensions. It is a completely non-destructive technique and can be implemented under normal conditions.

Potential applications for the analysis system

Near-field microscopy is suitable for a range of applications. When used in close consultation with the developers of new semiconductor components, for instance, the method can help optimize process parameters in a targeted way. The analysis also aids in the understanding of physical processes from a very early stage in development, particularly at the interfaces between the individual layers. These findings can shape subsequent development stages significantly. In high-frequency and power electronics, too, GaN is becoming more and more common as a component due to its physical properties. Near-field microscopic analysis techniques are ideally suited for researching these materials.

Contact

Dr. Fabian Gaußmann
Laser Measurement Technology
Phone +49 241 8906-489
fabian.gaussmann@ilt.fraunhofer.de
Fraunhofer Institute for Laser Technology ILT

Prof. Thomas Taubner
I. Institute of Physics (IA)
Phone +49 241 80 20260
taubner@physik.rwth-aachen.de
RWTH Aachen University


Weitere Informationen:

http://www.ilt.fraunhofer.de
http://www.rwth-aachen.de

Petra Nolis | Fraunhofer-Institut

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>