(SiGe) A semiconductor material made from silicon and germanium. Germanium is very similar to silicon, but when one layer is grown on top of the other to form the base of the transistor, the resulting transistor can switch faster and yield higher performance.
SiGe transistors are compatible with standard fabrication processes and are built on the same chip with silicon transistors to create high-frequency circuits. Only a handful of SiGe transistors are used in mobile phones, while tens of thousands are used in optical switches, DACs and ADCs. See
silicon and
strained silicon.