No extraneous sounds, vibrations or electromagnetic fields find their way into the noise-free lab at the Binnig and Rohrer Nanotechnology Center in Rüschlikon. Moreover, a temperature sensor ensures that experiments on new switching elements for computer chips are not affected by temperature fluctuations.
Today, a single computer chip contains over a billion transistors, a far cry from the ten transistors in the first integrated circuit in 1958. In the intervening years, the structures have become so small that individual layers are just a few atoms thick. This has created a new problem of electrons flowing between layers. In order to prevent this from happening, researchers are endeavoring to reinvent the transistor and to explore new types of components.
The solution lies in silence
Switzerland is home to a world-renowned laboratory in which scientists are working on the transistors of the future: the IBM research laboratory in Rüschlikon. The location’s easy accessibility is not exclusively advantageous: when a truck passes by, it causes the samples to shake under the electron microscope. In 2011, the Binnig and Rohrer Nanotechnology Center opened six integrated laboratories with exceptionally high protection against external factors: the noise-free labs. They are built directly on rock, the actual measurement set-ups mounted in turn on concrete blocks that float on a cushion of air. Forty-ton trucks can now race by without vibrating the sample. Another problem is noise. To keep it out, the labs are equipped with thick doors. Even the scientists present were too loud and were obliged to control the experiments from a separate room.
Precise room temperature
A temperature difference of just a few degrees would be capable of moving a sample by several 100 nanometres per hour with disastrous consequences for structures in the range of 1 – 50 nanometres. A sensor is therefore used to measure the temperature and air humidity. IBM is using a Rotronic transmitter capable of measuring temperature to 0.1 °C with absolute accuracy for this purpose. This corresponds to the maximum temperature drift permitted in the laboratory over a 1-hour period. At the same time, the sensor measures the relative humidity of the air which is required to remain within 35 and 55 %RH and not fluctuate by more than 5 %RH. The sensor is even capable of measuring the air humidity to exactly 0.8%RH thanks to an integrated chip.
Researcher Heike Riel makes good use of the quantum effects to develop small transistors that are also highly energy efficient. Instead of an operating voltage of somewhat over 1 V commonly employed today, they would work with voltages of less than 0.5 V. Rolf Allenspach aims to utilized electron spin: spin-up corresponds to a logical 1, spin-down to a logical 0. The chief attraction of this is that much less energy is required to change the spin than to displace the electron as is the case in transistors today.