By far, the most common digital integrated circuits built today use CMOS logic, which is fast, offers high circuit density and low-power per gate.
As of 2010, CPUs with the best performance per watt each year have been CMOS static logic since 1976.
Shown on the right is a circuit diagram of a NAND gate in CMOS logic.
Initially CMOS logic was slower than LS-TTL.
This high mobility allows the fabrication of higher-speed P-channel field effect transistors, which are required for CMOS logic.
CMOS logic reduces power consumption because no current flows (ideally), and thus no power is consumed, except when the inputs to logic gates are being switched.
However, unlike CMOS logic, NMOS logic consumes power even when no switching is taking place.
With advances in technology, CMOS logic displaced NMOS logic in the mid-1980s to become the preferred process for digital chips.
SiGe allows CMOS logic to be integrated with heterojunction bipolar transistors, making it suitable for mixed-signal circuits.
They have smaller areas than conventional CMOS logic (as does all Dynamic Logic).