Abstract: A sub-micron, on the order of 80-nanometer diameter, resonant tunneling diode having a peak-to-valley ratio of approximately 5.1 to 1, and a method for its manufacture. The invention is unique in that its performance characteristics are unmatched in comparably sized resonant tunneling diodes. Further, the polyimide passivation and planerization methodology provides unexpected processing advantages with respect to application in the fabrication of resonant tunneling diodes. The invention includes a substrate 706 that serves as a foundation for bottom contact layers 708 and a polyimide 700 coating. An ohmic metal contact 702 and emitter metal contact 704 protrude above the polyimide 700 coating exposing the ohmic metal contact 702 and emitter metal contact 704. The contacts are capped with an etch resistant coating 710 thus allowing for the polyimide etch, and other etching processes without adversely affecting the contacts.