Researchers have developed a new gallium nitride-based electrical component called a resonant tunneling diode (RTD) with performance beyond the anticipated speed of 5G. The RTDs compare well in both frequency and output power to RTDs of different materials. The diodes enable extremely fast transport of electrons to take advantage of a phenomenon called quantum tunneling. In this tunneling, electrons create current by moving through physical barriers, taking advantage of their ability to behave as both particles and waves.
The design for gallium nitride-based diodes displayed record current outputs and switching speeds, enabling applications requiring electromagnetics in the millimeter-wave region and frequencies in terahertz. The team developed a repeatable process to increase the diodes yield to approximately 90%; previous typical yields ranged around 20%.
Accomplishing a high yield of operational tunneling devices can be difficult because they require sharp interfaces at the atomic level and are very sensitive to many sources of scattering and leakage. Sample preparation, uniform growth, and a controlled fabrication process at every step were necessary to the diodes’ satisfactory results on a chip.