The miniaturisation of electrical components used in computing devices has been a 40-year trend. The amount of miniaturisation and performance, as well as the diversity of electronic devices, has advanced considerably in these decades. Following Moore’s law, the number of transistors that can fit into the same-sized integrated circuit has been doubling every 1,5 years as a result of nearly constant technological progress. Conventional computers that once filled buildings are now easily fitted into the palm of one’s hand.
As transistors are an important component in any electronic device, a lot of research work has been carried on to reduce the size of these transistors. Miniaturisation of conventional silicon chips is close to reaching fundamental limits, as the smallest silicon transistors that are currently available are of the 45 nanometre range. Reducing the size of these components further will result in smaller, powerful and energy-efficient electronic devices.
A team of researchers from the University of Pittsburgh has developed a new class of electronic devices that could be used to make both nanoscale transistors and high-density memory devices. The team has developed a nanoscale one-stop shop, a platform to create electronic devices very close to the single atomic scale. The idea of developing the already existing devices at the nanoscale level from the same material that has been conventionally used, was inspired by the microscopic Etch A Sketch, a drawing toy.
The system developed by the team consists of two layers, one made from a crystal of strontium titanate with another layer of lanthanum aluminate (three atomic layers thick). Both layers are by themselves insulators. The researchers have been able to modify the properties of the interface between these two materials so that it can be converted into a conductor, and it can be switched back and forth based on the requirement.
An atomic force microscope is used to draw lines on top of the layers, like the Etch A Sketch. With this technique, circuitry that is just 5 atoms wide can be drawn. The researchers hope that eventually only one electron will be needed to store one bit of information or operate the transistor.
The best feature of this technique is that the lines drawn on the layers in the chip can be erased or modified without the necessity of any complex procedures. The team developed a transistor that is 2 nm in size and named it SketchFET, which is significantly smaller than the currently existing 45 nm silicon chip. This technique could be used to create a wide variety of electronics and information technology. In addition, nanowires of desired pattern and length can be made using this proposed technology.
The characteristic features of SketchFET transistors are similar to those of silicon transistors and their applications are very promising. The SketchFET transistors can be erased if required and replaced by devices such as high-density memory, wiring or chemical sensors. It is anticipated that the development of this technique will mainly benefit nanoelectronics and the sensor field.
Using this technique, different processing circuits or memory devices can be designed and erased on the chip depending on the requirement. Apart from the electronics industry, other industries that would benefit from this innovation are information technology and biotechnology, by developing sensors that are sensitive to biological agents.