Emitter-Coupled Logic Circuits Implemented with Heterojunction Bipolar Transistors

This paper describes the first experimental demonstration of ECL circuits using (Ga,Al)As/GaAs heterojunction bipolar transistors. Ringoscillators were fabricated which exhibited propagation delay times as low as 185 ps, with devices fabricated on the basis of 2 μm design rules. Potential advantages of GaAs ECL circuits, their fabrication technology and their expected future performance are also discussed.