Collaborative Research: Low-noise high electron mobility transistors with outstanding noise performance via atomic layer etching

This program aims to create semiconductor amplifiers with outstanding noise performance in the microwave spectrum. Researchers from the California Institute of Technology (CalTech) and the University of Nevada-Reno (UNR) will accomplish this goal by leveraging a new nanofabrication method, atomic layer etching, which permits semiconductor device manufacturing with atomic-scale precision. If successful, these new amplifiers will be 30% more sensitive to radio emissions from space, meaning that less time will be needed for radio telescope measurements than is currently needed, potentially enabling new scientific discoveries. Based in part on this research, the team will develop a new college course at the UNR on nanofabrication, which will bring new technical training opportunities to students at UNR and in Northern Nevada. High electron mobility transistors (HEMTs) are used ubiquitously throughout radio astronomy observatories. Despite their impressive noise performance, their noise temperature has plateaued in recent years, in part due to challenges in scaling their dimensions even smaller. This project aims to overcome these limits by leveraging a new nanofabrication method, atomic layer etching, into the fabrication of low-noise HEMTs for the first time. The microwave noise performance has potential to improve by 30%, thus enabling significantly improved observational efficiency. These new HEMTs will be directly deployable to radio telescope systems as a drop-in replacement for the low-noise amplifier, meaning that an immediate improvement in sensitivity can be achieved without requiring any other upgrades. To maximize the broader impact of this project, the team will develop a new course on nanofabrication at the University of Nevada-Reno as well as incorporate graduate research activities into their new cleanroom facility. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.