1. New generations of CMOS

CMOS technology has made spectacular progress since the 1980s, when it became the dominant integrated circuit technology. As shown in figure 1 , new generations, known as technology nodes, have appeared regularly. These nodes were first defined in terms of transistor channel length, while the latest ones have been defined more in terms of marketing criteria. Moving from one node to the next has two essential effects:

• reduction in logic gate propagation times, enabling higher operating frequencies;

• increase in the number of transistors per unit area.