Advances toward smarter, smaller, and more durable electronics are being driven by the constant development of technologies and materials. Including vacuum layers in these miniature devices could address existing limitations since vacuum does not fatigue, has low dielectric loss, and transfers no stress. At the same time, the absence of matter opens up further opportunities and allows for the integration of extremely high electric fields. Oles et al. developed a proof-of-concept device that incorporated vacuum layers in a semiconductor device, achieving higher electric breakdown fields than any other known material.

The authors found their vacuum gaps withstood electric fields of up to 6 Gigavolts per meter. They investigated the current flow across the vacuum and the influence of electrostatic forces, providing essential characteristics for potential real-world use.

“The predictions of a high breakdown field for vacuum have existed for a long time, but for sub-micron distances, this behavior is often impaired because of the geometry of the device or the materials used,” author Peter Oles said.

To characterize vacuum gaps on a chip level, the team developed and manufactured semiconductor capacitors, and they used silicon electrodes and symmetrical geometries to apply extremely high electric fields across the vacuum gaps. They fit the leakage current to a characteristic Fowler-Nordheim electron tunneling model and determined the destructive breakdown strength by correlating their experiments with simulations.

The researchers consider it necessary to continue characterizing their vacuum gaps, such as investigating how the behavior changes under different conditions and how it evolves over time.

Source: “Integrated sub-micron vacuum gaps in semiconductor devices,” by Peter Oles, Alexander Breymesser, Oliver Blank, and Peter Hadley, Applied Physics Letters (2022). The article can be accessed at https://doi.org/10.1063/5.0097043.