Researchers at The National Physical Laboratory (NPL) have been examining alternatives for extending Moore's Law beyond the upcoming 22 nm process node around 2020. This iterative step is generally considered to be a hard barrier where the laws of physics finally tell Moore's Law "end of the line."
While most industry experts believe 22 nm will be the maximum achievable process shrink using silicon, this due to extraordinary quantum and heat effects observed at such levels, there are many researchers looking for alternate solutions to push beyond.
The quantum and heat effects observed at such small feature sizes begin to impede transistor function because there are very small quantities of silicon and copper doing the work. Small quantities of these substances means they use less power and can switch faster, but it also means other effects are far more pronounced as the signal-to-noise ratio is greatly reduced.
NPL researchers believe they may have found a new set of materials which could keep Moore's Law going long after 22 nm and 2020.
NPL's solution comes atop a manganese-doped (Mn) germanium (Ge) substrate. There, Ge nanowires are created and artificially magnetized. NPL reports the magnetizing effect exhibits properties which demonstrate "the potential of using these nanowires as building blocks for electronic devices," such as "ferromagnetism above 300 K and a superior performance with respect to the hole mobility of around 340 cm2/Vs and other industrially relevant parameters."
Ge is used today for very high-speed applications. Those involving a mix of silicon and germanium are gaining popularity as an alternative for high-speed needs. Ge is also used heavily in fiber-optics, infrared optics and solar cells. It has been shown capable of extremely high speed operations in the lab, but is difficult to manufacture in large sizes or mass quantities because it is extremely brittle.
Ge also spontaneously grows very long metal spiral extrusions which rise out of its surface. Called "whiskers," they often short-circuit Ge-based products and cause failures in long-running electronic devices.
Moving on to other materials
According to senior research scientist, Dr. Olga Kazakova, "The solution lies in changing not only the material but also the structure of our transistors. We have worked mainly with germanium nanowires that we have made magnetic. Magnetic semiconductors don't exist in nature, so they have to be artificially engineered. Germanium is closely compatible with silicon, meaning it can easily be used with existing silicon electronics without further redesign. The resulting transistors based on NPL's germanium nanowire technology, which could revolutionise computing and electronic devices, could realistically be 10 years away."
A paper describing their research has been published in Nano Letters. NPL is part of UK's National Measurement Institute, and is responsible for marrying scientific discoveries to real-world applications.
Source: TG Daily