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The meaning of discovery made by Czochralski and the future of Graphene

  1. 04 February 2014


A short interview concerning where I talked about SIlicon and Graphene.

What is the meaning of discovery monocrystalline silicon, made by Czochralski?

Jon Czochralski discovered in 1916 what njow is called Czochralski Process, a process to growth of large single crystals of exceptional quality and for the production of semiconductor wafer.
Czochralski discovered this process by accident in 1916 while investigating the crystallization rates of metals.
The most important application may be the growth of big silicon crystals. They can measure 2m by 0.5m and can be made within 30 to 48 hours. Then are chipped off in very thin sheets and used in transistors and for the production of microprocessors

His first discovery in the beginning of the 20th century was rediscovered later in the middle of the century by American semiconductor technology specialists who named his crystal pulling technique the "Czochralski method".

What has caused interest in his discovery, after years when he was mainly a subject of chemists interests?

The Czochralski method was completely forgotten for years. In the first part of the last century it was used mainly for studying the grow rate of some metals.
However, after the war scientists became interested in the growth of various materials applied in electronics technology because of the discovery of transistors.
In fact, increasing demand for semiconductor electronics materials in 1950 led the Americans G.K. Teal and J.B. Little from Bell Telephone Laboratories to rediscover and widely apply this growth method, giving it a world-wide fame to the Czochralski method for growing large single crystals on an industrial scale.
The natural growth process would take much too long and would be limited to very small sizes of crystals, making it unviable for industrial production of electronics.
The level of miniaturization that can be achieved today would be impossible to attain. Basically, computers would still be the size of an entire room, instead of the palm of your hand.

Crystalline Materials

How the monocrystalline silicon is used today? How it is applicable?

The Czochralski process is the base for semiconductor chips.
In fact the monocrystalline silicon form is used extensively in solid-state devices, in the computer and microelectronics industries because of its incredible quality and the total absence imperfections in the microstructure of silicon.
Without the crystalline perfection, it would be virtually impossible to build high integrated devices, in which millions of transistor-based circuits, all of which must reliably be working.
Monocrystalline silicon plays also an important role in the photovoltaic industries where high efficiency solar cells use the sun’s rays to generate space and water heating, produce domestic and industrial electricity.
Even at CERN, in all the experiments operating in the LHC accelerator, silicon wafers grown with Czochralski process are widely used. Radiation detectors made of Czochralski silicon are considered to be one of the best candidates for the future high-energy physics experiments due to their exceptional quality and radiation hardness proprieties.

How Czochralski's discovery influenced the development of our civilization?

Large size silicon monocrystals, grown with Czochralski process, have been used for over 40 years now as a standard material in semiconductor industry all over the world. Some scientific areas, such as the microelectronics, the solid state physics as well as the materials science, which created the foundation of modern technology, owe, at least in part, their progress and present position to the Czochralski's discovery.
His discovery has proven vital for electronic revolution as we know it today and it has been the key for the computer diffusion that has brought all the house Personal Computers smartphones. From the perspective of almost the past century the common opinion of the scientific community recognized him as a great scientist who has laid the foundation for the development of the global electronics.

czochralski cern

Are you aware of any other discoveries and inventions made by Jan Czochralski?

It's not only on crystals that Czochralski worked on. During his entire professional life he was a very active and competent scientist, able to identify most important aspects of physical problems to understand them, and finally to find successful application of the conceived ideas.
As matter of fact he made discoveries in metallurgy used for the development of wheels that allowed trains to go much faster than before.
Czochralski was also a pioneer in what is now described as technology transfer. He register a high number of patents in Germany and Poland. In addition during the war, when he worked at the Technical University of Warsaw, he developed an easily manufacturable grenade for the Polish resistance.
To conclude, history confirms that he was distinguished scientist and inventor. It should be also underlined that he had very modern views on the role of engineering sciences. Much of his research was driven by the needs of industry and the search for new technologies

Do you think that the graphene production on an industrial scale is/would be a breakthrough similar to the invention of method of obtaining single crystals of silicon?

Both science and the industry place high hopes in graphene.
It's considered as the wonder material of our century with the power to revolutionise micro-electronics. Just one atom thick, the novel form of carbon is the world's thinnest and strongest nano-material, almost transparent and able to conduct electricity and heat.
Graphene transistors would in theory be able to run at faster speeds and cope with higher temperatures than today's classic silicon computer chips. That, would resolve a fast-growing problem facing chip engineers, who want to boost power and shrink semiconductor size but without raising temperatures. Graphene's transparency also means it could potentially be used in touch screens and even solar cells, and when mixed with plastics would provide light but super-strong composite materials for next-generation planes and cars.
But the problem so far has been a lack of methods to turn out layers of it. Single sheets of graphene are hard to produce and even harder to make on an appropriate substrate. While it is currently possible to produce graphene layers, relatively large ones can only be made on a metal base. That hampers graphene's electronics potential. Without such a base, current techniques only allow for a maximum layer surface of four square inches (25 square centimetres).
Now Polish scientists, from the Institute of Electronic Materials Technology say they have discovered a new method to produce entire layers of graphene, a move that should help to propel it out of the lab and into everyday life. This is an important step forward on the path to the production of transistors and then integrated circuits made of graphene.
The great hope is that, as happened to Czocharlski in the past, the polish scientists can develop a new and reliable production process that will revoluzionize the world.

interview stefano meroli 

If there is a possibility to link/combine them? How?

Graphene poses a significant challenge, though: in contact with other materials, it changes significantly and loses its potential.
Some scientists were able to combine silicon and graphene, in particular in the domain of radiation detector. They were able to combine graphene light detectors with standard silicon chip.
But, the super-conductivity and transparency of graphene, could make it the ideal candidate to produce super-efficient solar cells: it does not stop incoming light rays and allows electricity to move fast through its carbon atom lattice.
This was achieved by growing graphene on a copper foil, then moving it to a glass substrate and coating it with a silicon film. Measurements showed that silicon-coated graphene has a power conducting capacity 30 times higher than traditional materials. This is an important achievement that, however, still requires lots of efforts.
But the big hope of micro-electronic engineers is to use graphene, combined with silicon, for future CPUs working at 1THz — that means 1000GHz.
Also in this case, a big effort should be put in place for the development of a reliable industrial process capable to combine graphite and other semiconductors.

References

  1. S. Meroli, Two growth techniques for mono-crystalline silicon: Czochralski vs Float Zone, (2012).