InGaAs/AlAs Resonant Tunneling Diodes with Very High Negative Differential Conductance for Efficient and Cost-Effective mm-Wave/THz Sources

The work reported here demonstrates double barrier InGaAs/AlAs resonant tunneling diodes with both high current density and negative differential conductance features. The simplicity of the device epitaxial structures exploited in this work (avoiding graded or/and quaternary layers) makes it attractive for manufacturing. An extracted negative differential conductance of 95 mS/ μm2 was deduced for RTD sample #327. This device had a high current density of 10.8mA/μm2 while still maintaining an excellent PVCR of 5, one of the highest ever reported for such a high current density making the diode suitable for low-cost mm-wave/THz regime applications. These prominent features boost the estimated intrinsic cut-off frequency of the device beyond 2THz for a relatively large mesa size of 2 μm2.