CMOS dynamic-RAMs approach static RAM speeds

摘要

In the last few years, it has become clear that CMOS is emerging as the dominant MOS I.C. technology. In the mid-70s, CMOS integrated circuits had already been produced in relatively large volumes, however, the process was thought to be mainly suitable for specialty applications in which extremely low power or wide operating voltage margins were required and in which overall speed was not particularly important. The complexity of CMOS processing as well as its relatively low packing density were also thought to be serious drawbacks to its use as a mainstream I.C. technology. Beginning in the mid-70s, however, power dissipation rather than yield considerations began to limit the amount of NMOS circuitry capable of being integrated into a single chip. As circuit designers turned to CMOS as a possible solution, it was found that clever uses of P-channel transistors could actually improve speed over many types of traditional NMOS circuits and that the complexity and density gap between CMOS and NMOS processes had narrowed considerably due to increasingly complex NMOS processes.