Picosecond Integrated Circuits in Germanium and Silicon

Recent advances in semiconductor technology make possible a planar technology for germanium similar to that used for silicon integrated circuits. Calculations based upon material properties indicate a considerable advantage to germanium over silicon for high-speed logic-switching applications.This is due largely to the better electron and hole mobilities for germanium. Switching circuit delays have been measured in both germanium and siliconin hybrid and integrated circuit form. For a given level of device sophistication (measured in terms of the stripe widths used on the devices) the germanium circuits are about three times faster than the equivalent silicon circuits.