InGaAs zero bias backward diodes for millimeter wave direct detection

Backward diodes are a version of Esaki tunnel diodes that are useful for mixing and detection. Ge backward diodes in particular have been used as temperature insensitive, zero bias square law detectors, capable of translating input RF power into dc voltage or current with extreme linearity and low noise. However, Ge diodes are difficult to reproducibly manufacture and are physically fragile. Here we demonstrate specially designed InGaAs-based backward diodes grown by molecular beam epitaxy. These diodes have superior figures of merit compared to Ge diodes, are reproducible and physically rugged, and are compatible with InGaAs high electron mobility transistor (HEMT) low noise amplifier fabrication technology. In addition, the flexibility of MBE growth allows easy tailoring of the layer structure to maximize the desired figure of merit for a given application.