Roll-to-Roll Synthesis of Silicon Thin Films from Liquid Silanes (RFT-447)

Invention Summary

Silicon thin films are fundamental in solar and microelectronic industries, and are presently obtained using expensive low-pressure plasma enhanced chemical vapor deposition (PECVD) using gaseous silanes despite of its low precursor utilization efficiency. Instability and low vapor-pressure of liquid hydrosilanes have limited their use in the semiconductor industries for longtime. Researchers at NDSU have developed a process to synthesis silicon thin films from liquid hydrosilane (Si6H12) at ambient pressure in a roll-to-roll method using atmospheric pressure aerosol assisted chemical vapor deposition (AA-APCVD) that has higher deposition rates compared to the state-of-the-art PECVD. Solubility of solid dopants in the liquid hydrosilane facilitate the deposition of degenerately doped (n & p –type) Si thin films opposed to compressed toxic phosphine and borane gases used in other techniques. Low decomposition temperature (higher activation energy) of cyclohexasilane (Si6H12), a liquid hydrosilane, benefits for a new plasma-free process for the synthesis of silicon nitride films and Si nanowires (with suitable catalyst) at temperatures as low as 350oC using the AA-APCVD, readily adoptable for large-scale roll-to-roll continuous manufacturing. Liquid hydrosilane compositions consisting of nanomaterials enable hybrid Si films with embedded nanomaterials that have applications in energy harvesting and light emitting devices.



  • Roll-to-roll, ambient pressure, low temperature, high deposition rate
  • Soluble dopants allow degenerately doped Si thin films without PH3 and B2H
  • Plasma free synthesis of a-SiNx thin films
  • Vapor-Liquid-Solid based growth of Si nanowires and nanomaterials embedded Si thin films


These inventions have applicability in photovoltaics, microelectronics, Li-ion batteries (anode), optoelectronic devices and biomedical market.


This technology is the subject of the Issued US patent 9914998 and is available for licensing.


NDSU Research Foundation


RFT, 447, RFT447

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