Ruthenium Films with C-Axis In-Plane Crystallographic Orientations

  • Single crystal ruthenium (Ru) thin films grown with the c-axis parallel to the substrate plane
  • Configuration process enables a low-resistivity crystal structure orientation
  • Can be used as interconnects or electrical connections in semiconductor devices

Abstract
Researchers at the University of Central Florida and Columbia University have developed a novel thin film process for metal deposition (single crystal ruthenium, Ru) to achieve low resistivity in semiconductor interconnects. They observed 40 percent lower resistivity in bulk materials and expect to see a similar or greater advantage in nanowires. The invention provides for lower resistivity wires and nanowires. It can also support applications in electronic and optical devices that use an anisotropy of electrical conductivity. Ru thin films are important for next‐generation semiconductor interconnects (nanowires) due to their low resistivity and high melting temperature.

Technical Details

The invention comprises a device and methods for creating ruthenium (Ru) thin films with a crystallographic surface net that promotes non-perpendicular c-axis orientations. While Ru films typically form with the c-axis perpendicular to the surface of a substrate or as a polycrystalline film with a random crystallographic orientation, the invention enables the configuration of net crystallographic surfaces that promote non-perpendicular c-axis orientations of Ru. The substrate may be formed with a metal-terminated surface in certain arrangements.

In one example, researchers achieved a low-resistivity crystal structure orientation by placing a few monolayers of high oxygen affinity metal (aluminum) on the insulating substrate before the deposition of the Ru. This induced the single crystal Ru film to grow with the c‐axis parallel to the substrate plane. In certain embodiments, the c-axis can be arranged to be a) parallel to a film plane, or b) no more than about 10 degrees from parallel to a film plane.

Stage of Development

Prototype available.

Contact Information

Name: Andrea Adkins

Email: Andrea.Adkins@ucf.edu

Phone: 407.823.0138