As there is a finite number of transistors that can be effectively packed onto a silicon chip, researchers have been searching for an alternative to silicon that would allow integrated circuit development to continue to keep pace with Moore's Law. Researchers at MIT have recently used indium gallium arsenide to create the smallest transistor ever built from a material other than silicon. The new transistor, which is said to “work well,” is just 22 nanometers long and is a metal-oxide semiconductor field-effect transistor (MOSFET), which is the kind typically used in microprocessors.
While nanoscale silicon transistors have also been built, the amount of current that they are able to handle is very limited by their small size. This is why there’s the potential for silicon microchips to simply “max out” – in order to fit more transistors onto a chip, they have to be smaller, but they simply can’t get much smaller and still work.
The electrical properties of indium gallium arsenide, however, allow the tiny new MIT transistor to still handle a decent current – due to its high conductivity, indium gallium arsenide has also found use in fiber optics and solar cells. Because the transistor is much smaller than a regular silicon transistor, yet still performs well, this means that a greater number of them could be crammed onto a chip, and Moore’s Law could continue.
The researchers now plan on further decreasing the transistor’s electrical resistance, to boost its performance and to allow its size to be reduced even more.
“We have shown that you can make extremely small indium gallium arsenide MOSFETs with excellent logic characteristics, which promises to take Moore’s Law beyond the reach of silicon,” said one of the chip’s co-developers, Prof. Jesús del Alamo.
Scientists from Purdue and Harvard universities have also been developing indium gallium arsenide transistors – with a three-dimensional structure.
Update: This story was amended on Dec. 14, 2012, to reflect that transistors don't produce current.