High‐speed logic circuits combining bipolar and CMOS technology

Abstract

AbstractIt has been verified that a new LSI concept with high speed and low power consumption can be realized by combining bipolar and CMOS technology inside a basic unit circuit. This paper proposes a combined basic circuit that is of the high‐speed logic type. It is theoretically and experimentally evaluated to show that specified performance can be obtained, and some effective applications are analyzed. Using the circuit model, the relatioship between the performance of logic cicuit and the basic characteristics of the devices are analyzed, and the collector current vs. fT characteristics of bipolar device is shown to be important. Ring oscillators are fabricated for the two concrete circuits, and the speed and power conssumption are evaluated. The fabrication uses a newly developed Bi‐CMOS 2 μm technology which has buried layer and a small‐sized emitter for bipolar device with good high frequency characteristics. As a result, with a standard load and operation frequency, the delay of 0.7‐0.8 ns, and the power consumption of 0.15‐0.25 mW are obtained. By applying this logic circuit to gate arrays and memories, twice the speed of a CMOS can be realized with the same amount of power consumption.