Tunnel diode/transistor differential comparator

A new tunnel diode/transistor circuit topology is reported, which both increases speed and reduces power in differential comparators. This circuit topology is of special interest for use in direct digital synthesis applications. The circuit topology can be extended to provide performance improvements in high speed logic and signal processing applications. The circuits are designed based on InP/GaAsSb double heterojunction bipolar transistors and AlAs/InGaAs/AlAs resonant tunneling diodes. A self-aligned and scalable fabrication approach using nitride sidewalls and chemical mechanical polishing is outlined.