CMOS-Compatible Single Crystal Metal Growth

Researchers in Profs. Jonathan Fan and Jim Plummer's laboratory have patented a generalized, CMOS-compatible process to fabricate single crystal metal components on amorphous insulator substrates. This technology is based on a liquid phase epitaxy process for single crystal growth (see US Patent 7,749,872) and can be used with a range of materials to create single crystal metal structures on conventional insulating surfaces such as amorphous silicon dioxide. The dimensions of these microstructures range from a few microns wide and hundreds of microns long. Without grain boundaries, these structures exhibit vastly superior electrical and optical performance compared with their polycrystalline counterparts.

In the short term, these devices can serve as a model system for the study of single crystal metal integration into electronic and metal-optical platforms. In the long term, this materials platform can integrate with electronic and optical system, leading to: enhanced operational speed and energy consumption of integrated circuits; reduced parasitic losses in plasmonic optical technologies; and reduced electrical and mechanical failure due to electromigration.

Liquid metal epitaxy process with gold microstripes and platinum seed structures.: Large-area EBSD image of processed gold stripes. The color map (Lower Left) describes the orientations of the crystal plane normals. (Inset) SEM image of an individual gold stripe. The coordinate system denotes the axes for EBSD analysis: x axis along the stripe, y axis transverse to the stripe, and z axis normal to the stripe and substrate. (Scale bars: 20 ?m.)

Stage of Development – Prototype
The inventors have used this technique to create single crystal gold structures on amorphous oxide wafers.