Process integration and device performance of a submicrometer BiCMOS with 16-GHz f/sub t/ double poly-bipolar devices

Abstract

Submicrometer-channel CMOS devices have been integrated with self-aligned double-polysilicon bipolar devices showing a cutoff frequency of 16 GHz. n-p-n bipolar transistors and p-channel MOSFETs were built in an n-type epitaxial layer on an n/sup +/ buried layer, and n-channel MOSFETs were built in a p-well on a p/sup +/ buried layer. Deep trenches with depths of 4 mu m and widths of 1 mu m isolated the n-p-n bipolar transistors and the n- and p-channel MOSFETs from each other. CMOS, BiCMOS, and bipolar ECL circuits were characterized and compared with each other in terms of circuit speed as a function of loading capacitance, power dissipation, and power supply voltage. The BiCMOS circuit showed a significant speed degradation and became slower than the CMOS circuit when the power supply voltage was reduced below 3.3 V. The bipolar ECL circuit maintained the highest speed, with a propagation delay time of 65 ps for C/sub L/=0 pF and 300 ps for C/sub L/=1.0 pF with a power dissipation of 8 mW per gate. The circuit speed improvements in the CMOS circuits as the effective channel lengths of the MOS devices were scaled from 0.8 to 0.4 mu m were maintained at almost the same ratio. >