DESCRIPTION
Silicon thin films play a crucial role in the solar and microelectronics industries. Currently, these films are primarily produced using expensive low-pressure plasma-enhanced chemical vapor deposition (PECVD), which relies on gaseous silanes but suffers from low precursor utilization efficiency. The instability and low vapor pressure of liquid hydrosilanes have long limited their applications in the semiconductor industry.
Researchers at North Dakota State University (NDSU) have developed a new process for synthesizing silicon thin films from liquid hydrosilane (Si6H12) at ambient pressure. This method employs atmospheric pressure aerosol-assisted chemical vapor deposition (AA-APCVD) in a roll-to-roll format, achieving higher deposition rates compared to the conventional PECVD technique.
The solubility of solid dopants in liquid hydrosilane allows for the deposition of heavily doped (n-type and p-type) silicon thin films, as opposed to using compressed and toxic gases like phosphine and borane found in other methods. Additionally, the low decomposition temperature and higher activation energy of cyclohexasilane (Si6H12) enable a new plasma-free process for producing silicon nitride films and silicon nanowires (with suitable catalysts) at temperatures as low as 350°C using AA-APCVD. This process is readily adaptable for large-scale, continuous manufacturing.
Furthermore, liquid hydrosilane compositions containing nanomaterials facilitate the creation of hybrid silicon films embedded with these nanomaterials, which have promising applications in energy harvesting and light-emitting devices.
Benefits
- 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 in Si thin films
Applications
These inventions have applicability in photovoltaics, microelectronics, Li-ion batteries (anode), optoelectronic devices, and the biomedical market.
Patents
This technology is the subject of the Issued US patent 9914998 and is available for licensing.
