C2L: A new high speed, high density bulk CMOS technology

A new structural approach to high speed COS/MOS, C2L, results in significant speed and packing density gains. The CDP 1802, single-chip, 8-bit microprocessor as well as several memory and I/O circuits announced recently by the RCA Solid State Division are fabricated in this new bulk CMOS technology, called C2L or Closed COS/MOS Logic. C2L is a self-aligned silicon gate CMOS technology where the gate completely surrounds the drain. This technique does not require the conventional guardbands of standard Al-gate CMOS and thereby significantly increases packing density as well as device speed, and still retains the inherent advantages of CMOS (very low static power dissipation, high noise immunity and operating voltage from 3 to 15 volts at temperatures ranging from -55°C to 125°C). The basic C2L device structure is presented and compared to standard Al-gate CMOS. The speed advantages of C2L devices are discussed, and data comparing the performance of C2L circuits with comparable standard CMOS devices is presented. Generally, C2L devices show an improvement in packing density by a factor of 3 over standard CMOS and operate at frequencies approximately 4 to 6 times faster than standard CMOS. The fabrication sequence for C2L devices requires 6 photomasks (one less than standard CMOS).