The TU Ilmenau develops tomorrow’s chip technology today

In this 18 million euro project, led by Professor Ivo W. Rangelow in Ilmenau, 16 industrial and scientific partners explored the technological processes behind the production of transistors, whose smallest components are only two nanometres in width, which is half a million times smaller than a millimetre.

The results of the project enable the mass production of a new generation of electronics, including incredibly energy-efficient and high-performance computers, smartphones and tables, to name only a few examples.

In the last 50 years, our modern information society has experienced incredible technological development. Electronic chips for computers, mobile phones and tab-lets are becoming smaller and more powerful than ever before.

The number of transistors on a single chip has been increased from 2,300 in 1970 to 1.3 billion today. 45 years ago, the smallest parts of those transistors were still just as big as the diameter of a human hair, around 75,000 nanometres. Today, this length is only 14 nanometres.

The size of electronic components is constantly decreasing, but the end of this min-iaturisation is in sight, at least when using conventional technologies. Experts pre-dict that the physical construction limits of today’s transistors will be reached be-tween the years 2025 and 2035.

Electronic devices that can perform well, as well as remain as energy-efficient as possible, not only require a completely new type of transistor, but also smaller and smaller structures for these semiconductor compo-nents. These minuscule structures must also be producible in large quantities. At the moment, such transistors can only operate in laboratories at extremely low temperatures of below minus 200ºC.

During this European joint project, “Single Nanometer Manufacturing for beyond CMOS Devices (SNM)”, a large European research team working under the leader-ship of Professor Ivo W. Rangelow optimised the preexisting production methods for fast electronic components and have enabled the production of electronic structures smaller than two nanometres.

The ground-breaking scientific results of the SNM project have made possible the mass production of a new generation of high-performance and energy-efficient electronics. A great step has been made: the smaller the structures built into a transistor, the greater the number of transistors on a CPU, and thus the more powerful the computer.

An increase in processing capability and storage space is urgently needed, considering the expansion of the internet into an internet of things that has long-since begun. Only in this way will it be possible to connect computers with more and more “smart” objects from our day-to-day lives in the digital world, so your computer, fridge and co. can all communicate together.

To this end, high processing power with the lowest possible energy usage is the goal. The battery capacity of mobile electronic devices, such as laptops and smartphones, is one of their biggest weak points. In order to reduce the energy usage of highly-integrated electronic circuits and thus of electronic devices them-selves, Prof. Rangelow and his research team either utilised current production methods in new ways or simply developed wholly new, innovative ones.

In this way, the energy usage of mobile devices could possibly be reduced by 2,500%. But Prof. Rangelow does advise against being overly optimistic: “The energy usage of mobile devices is dependent on so many factors that huge reductions might be theoretically possible, but cannot be scientifically and credibly predicted. But with our new methods we certainly have paved the way for technologies that allow us-ers to charge their mobiles far less often. Instead of every day, maybe only once every five days.”

The results of the SNM project were made possible through an interdisciplinary cooperation by 16 top-quality universities, research institutes and industry companies in eight European countries. In their research work, the 50 scientists used quantum effects to design ultra-small, so-called “single electron components”. As opposed to classical physics, quantum mechanics allows the physical properties of matter to be precisely measured down to the particle scale.

The scientific analysis of structures on scales below ten nanometres is incredibly time-consuming and was coordinated by the Dutch national metrology institute VSL, a world-leading institute of measurement technology. The measurements of the single electron components were carried out at Imperial College London, a British university, which aims to carry out world-class research in the natural and engineering sciences. These measurements confirmed that the smallest functional structures had a diameter of only 1.8 nanometres. When the SNM project began four years ago, diameters of 35 nanometres were achieved with traditional production methods.

The production of electronic components using lithography, an inscribing process, comprises two steps. Firstly, the structures are written in a coating layer. During this step, the shape for the second step is prepared, similar to the production of negatives in analog photography. Finally, the structures are etched from the coat-ing layer into the silicon; the “positive image”, the electronic component, is created from the “negative” of the first step. Until a complete ultra-small circuit can be produced, the individual, incredibly complex steps need to be carried out dozens, if not, hundreds of times.

Using so-called “slow electrons”, the scientists at the TU Ilmenau formed structures of sizes below 10 nanometres with one or multiple nano-sized needles. This inscribing process, named scanning-probe technology, allows not only for the patterning of nano-structures, but also allows them to be read and to be arranged incredibly precisely.

The development of electronic structures smaller than two nanometres is an outstanding achievement for Prof. Range-low: “Across the world, technologies that could realise the computer of the future, the quantum computer, are being intensively sought out and researched. In con-trast to traditional computers, these are exclusively based on the laws of quantum mechanics. Quantum computers will be incomparably more powerful, because they would allow us to avoid classic problems in computing, such as searching extreme-ly large databases. The scanning-probe technology we have developed, with which we can produce structures smaller than two nanometres, has opened the door to this new world of quantum computer a fair amount.”

12 million of the almost 18 million euros in funding for this EU joint project, “Sin-gle Nanometer Manufacturing for beyond CMOC Devices”, came from the seventh framework programme of the European Union; the remaining six million was sourced from international partners that took part.

The international partners of the TU Ilmenau made considerable, valuable contribu-tions to these new technologies:

• Thermal lithographic methods, which were invented by one of the worldwide leading hard- and software companies IBM and significantly enhanced for the SNM project, allowed for the production of ultra-small size and even three-dimensional components. IBM conducted research and development in close col-laboration with a young Swiss start-up firm, the SwissLitho AG. As a result of this project, SwissLitho launched the first commercial device for the production of ultra-small size electronic components on to the market: the NanoFrazor.

• The biggest public research center in Spain – the Consejo Superior de Investigaciones Científicas CSIC – presented new methods for the production of components made from nanowires with a thickness of less than ten nanometres.

• The British SME Oxford Scientific Consultants – dealing with research and development as well as prototype development – used a new writing technique successfully using helium ions instead of electrons.

• Coating layers, which are used for both lithography and the transfer of written structures onto the carrier material silicon, were improved to such an extent at the Universität Bayreuth that structures smaller than ten nanometres could be produced in silicon.

• The transfer into the silicon material is carried out with the help of etching pro-cesses, which have been adapted to structure processing in smallest dimensions and the use of the new coating layers. Alongside the TU Ilmenau and the Interu-niversity Microelectronics Centre IMEC, one of the biggest European research centres for nano- and microelectronics, the biggest state university in Great Britain Open University and Oxford Instruments, a British company developing scientific devices for industry and research, were involved in the entire project.

• The speed required for the mass production of electronic structures was achieved by the Austrian producer of wafer processing equipment, EV Group (EVG), with the help of the so called nano-imprinting lithography, in short nanoimprint. Fully automated processing solutions were developed for achieving throughputs of up to 30 substrates per hour. This is an exceptional increase to so far used manual systems and is compatible with production requirements. The Dutch Technische Universiteit Delft has developed a high-resolution lithographic process, increasing the speed significantly with the help of 25 electron beams rather than one.

Contact:
Prof. Ivo W. Rangelow
Director, Institute for Micro‐ and Nano‐electronics,
Head, Micro‐ and Nano‐electronics Systems Department
Phone: + 49 3677 69‐3718
Email: ivo.rangelow@tu‐ilmenau.de

http://www.tu-ilmenau.de/mne/