Parallel Synthesis of Nanoscale Si Superlattices through Eutectic Confinement for Semiconductor p–n Junctions

Superlattices are complex structures comprised of periodically ordered particles, wires, or slabs. Superlattices containing nanoscale to micron-scale layers of semiconductors underpin myriad quantum device architectures, light-emitting diodes, transistors, and memory elements. Current approaches for the fabrication of such superlattices typically offer a trade-off between high quality and high throughput. Here we report a parallel process for the rapid synthesis of nanoscale Si superlattices. Bottom-up growth of the superlattices is catalyzed by eutectic liquids confined within pre-etched trenches. Electron microscopy and crystallographic analyses reveal that nanoscale, highly oriented, and single-crystal slabs of Si are grown in an en masse fashion across large substrate areas. The synthetic process is highly selective toward bottom-up growth and exhibits growth rates in excess of 500 nm/min. Serial sectioning reveals that the Si slabs are uniformly crystalline and oriented with an average defect concentration of 1.4%. Using this method, we fabricate a superlattice of nanoscale Si p–n junctions and achieve phosphor dopant levels approaching 1 × 1020 atoms/cm3. This method provides a unique opportunity for the rapid fabrication of high-quality nanoscale semiconductor superlattices and devices.