Usually, a computer chip consists of electronic components. One component always does the same thing. However, in the future, greater flexibility will be possible: new adaptive transistors can dynamically switch at run time to perform different logic tasks. This fundamentally changes the possibility of chip design and opens up new opportunities for artificial intelligence, neural networks and even logic fields that can handle more values than 0 and 1.
In order to achieve this goal, scientists at the Vienna University of Technology (TU Wien) do not rely on the usual silicon technology, but on germanium. They succeeded in making the most flexible transistor in the world with germanium. The relevant research results were published in the scientific journal ACS Nano.
"The special properties of germanium and the use of special program gate electrodes make it possible for us to create a prototype of new components, which may usher in a new era of chip technology," the researchers said
The transistor is the foundation of every modern electronic device: it is a tiny component that allows or prevents current flow, depending on whether a voltage is applied to the control electrode. This makes it possible to establish simple logic circuits and storage. How the charge travels through the transistor depends on the material used. Either there is a free moving electron with a negative charge, or an electron may be missing from an individual atom, so this place is positively charged. These are called "holes" and they can also move in the material.
Among the new transistors at the University of Vienna, Both electrons and holes are manipulated simultaneously in a very special way: "We use a very thin germanium wire to connect the two electrodes, and connect the two electrodes through an extremely clean high-quality interface. Above the germanium section, we place a gate electrode like that in a traditional transistor. This transistor also has a control electrode, which is placed on the interface between germanium and metal. It can dynamically program the functions of the transistor."
According to the researchers, this device structure makes it possible to control electrons and holes respectively, because germanium has a very special electronic structure: when you apply voltage, the current will initially increase, as you expect. However, after a certain threshold, the current decreases again, which is called negative differential resistance. With the help of the control electrode, the researchers can adjust the threshold voltage. This leads to a new degree of freedom that can be used to give transistors the characteristics they currently need.
For example, in this way, a NAND gate can be switched to a NOR gate. "So far, the intelligence of electronics has simply come from the interconnection of several transistors, and each transistor has only one fairly primitive function. In the future, this intelligence can be transferred to the adaptability of new transistors themselves," the researchers said
"In the past, the arithmetic operation of 160 transistors was required. Due to the improvement of adaptability, 24 transistors can be realized. In this way, the speed and energy efficiency of the circuit can also be significantly improved." They added.
These new possibilities are particularly interesting for applications in the field of artificial intelligence: "Our human intelligence is based on dynamic circuits between nerve cells. With new adaptive transistors, we can now directly change the circuit on the chip. Multivalued logic can also be realized in this way, that is, the circuit works not only in 0 and 1, but also in a larger number of possible states."
In addition, the rapid industrial application of this new technology is also realistic: the materials used have been used in today's semiconductor industry without completely new manufacturing processes. In some ways, the technology will be even simpler than before: today, semiconductor materials are doped, that is, enriched by a single foreign atom. This is not necessary for germanium based transistors, which can use pure germanium.
"We don't want to completely replace the mature silicon transistor technology with our new transistor, which will be self righteous. In the future, this new technology is more likely to be integrated into computer chips as an add-on. In some applications, the use of adaptive transistor will be more energy-saving and convenient."
(Financial Associated Press)
