AFOSR Invests in Silicon Vacuum Transistors for Extreme Electronics

A scanning electron microscope image of the fabricated Field Emitter Array. 

In the 1950s, semiconductors began to replace vacuum tube transistors in digital computers due to their increased reliability. However, thanks to investments from the Air Force Office of Scientific Research (AFOSR), a team at Purdue University have developed a nanoscale silicon-based vacuum transistor for high-power high-frequency electronics and for use in harsh environments.

The Air Force has a need for robust electronics that can operate in high temperature, high radiation environments. Prof. Saeed Mohammadi, the lead Principal Investigator (PI) of the Purdue research team, with support from AFOSR Program Officer, Dr. Kenneth Goretta, has found a possible solution. AFOSR invested $650K in 2018, which not only resulted in amazing lab results, but also led to a published US Patent on 5 September 2023: “Silicon-based vacuum transistors and integrated circuits” (US 11,749,487 B2).

These nanoscale field emitter array (FEA) vacuum tube transistors are reliable in environments up to 300C and can operate under high, sustained radiation, such as inside a nuclear reactor, without mechanical failure.

The transistors leverage the speed of light in a vacuum, enabling low-power, high-speed electronics. This advantage has the potential to revolutionize telecommunications, data processing, and signal processing. Unlike traditional systems relying on volatile memory, vacuum transistors maintain data integrity during sudden power losses, ensuring instant data recovery.

Schematic of an application of the Field Emitter Array of the present disclosure as digital circuit implementations: a floating cathode field emitter logic technology with a compact 3D structure. Adapted from [US 11,749,487 B2]

Prof. Mohammadi’s breakthrough with nanoscale silicon-based vacuum transistors, supported by AFOSR, opens doors to a new era in electronics. The resilience, efficiency, and versatility of these transistors in extreme conditions promise far-reaching applications, from aerospace to data centers. The potential cost savings and superior speed make them a transformative force in technology. Their ability to safeguard data in critical moments cements their significance in the modern electronics landscape.

A variety of applications for this technology include: Aerospace and defense; Next-generation displays such as flat-panel displays, microdisplays and electronic papers; Electron microscopy; Electron beam lithography systems; Gas sensors, and radiation detectors.