Thermal laser epitaxy to unleash electronic-grade cubic boron nitride films
Abstract
The gold standard technique for the preparation of thin films that lie at the heart of the highest-performance electronics and optoelectronics is molecular-beam epitaxy (MBE). In the >50 years of its existence, MBE has become famous for providing atomic-layer control, sharp interfaces, high mobility, and heteroepitaxial integration for state-of-the-art devices as well as assessing the potential of new device concepts involving emerging materials with superior properties. The growth conditions of MBE are, however, limited in temperature and pressure. For the growth of thin films of materials containing nitrogen or oxygen, these limits are not fundamental; instead, they are set by where the resistive heating elements in the MBE that heat the source materials or the substrate melt or react with the nitrogen or oxygen background gas species. A new thin film growth method is emerging that looks to be the future of MBE because it retains the advantages of MBE as it broadens the reach of the technique to 100-fold higher pressures, unlimited higher temperatures, isotopic purity, and greater cleanliness. The technique is called thermal laser evaporation (TLE) and was invented in 2019 by a group in Germany. This group recently founded a company (Epiray, GmbH) to commercialize TLE. In TLE the components that provide the heating (powerful industrial layers with excellent stability and reliability) are all outside of the ultra-high vacuum environment, making the limit of TLE the pressure at which atoms in the molecular beams begin to collide with each other (the mean-free path), rather than the pressure at which heating elements fail. The higher temperatures and pressures possible with TLE are poised to facilitate the growth of hard-to-nitridize (oxidize) materials that are currently off-limits to nitride (oxide) MBE.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502410109
Entities
People
- Darrell G. Schlom
Organizations
- Air Force Office of Scientific Research
- Cornell University
- United States Air Force