Scalable high-current density RTDs with low series resistance

InP-based double-barrier resonant tunnelling diodes have been optimized for high speed digital circuits. We present the scalability of high current density (JP ≈ 150 kA/cm2;) resonant tunnelling diodes in the sub-micrometer electrode area range. A small signal equivalent circuit has been developed and its parameters are precisely deduced from DC and RF measurements. Based on this model the scalability has been investigated with emphasis on a low but also scalable series resistance in order to keep the peak voltage constant. A comparison of dry and wet etching methods in the device fabrication will be presented. A multiple mesa concept has been adopted to provide reliable scalability at low emitter area (AE < 1 µm2).