A Georgia Tech research team paired with IBM has recently demonstrated new Silicon-Germanium transistors capable of operation at over 500GHz. That is roughly 250 times faster than the transistors found in your common cell phone. These experimental transistors attained this speed at a temperature 451 degrees Farenheit below zero through the use of liquid helium. Researchers say that at room temperature these chips can operate at 350GHz.
SiGe is a process technology in which the electrical properties of silicon, the material underlying virtually all modern microchips, is augmented with germanium to make chips operate more efficiently. SiGe boosts performance and reduces power consumption in chips that go into cellular phones and other advanced communication devices. Source: GT Research News
Once optimized, these fourth generation SiGe chips should be able to run at near Terahertz frequencies at room temperature. There are many advantages to including Germanium into the transistor manufacture process. However, the most substantial benefit is the ability to mass-produce these transistors with current silicon-based fabrication techniques. I eagerly await the time when I will be using a computer powered by a processor made completely from Silicon-Germanium transistors like these.
The black squares are the Silicon-Germanium transistors being developed at the Georgia Electronic Design Center on Georgia Tech campus.