Amorphous Silicon Advantages
The silicon most people are familiar with is the crystalline form found in computer semiconductor chips. The silicon in these chips is created by atomic layer deposition (ALD) in a crystalline form. Also, the early development of silicon anodes in the EV industry builds upon this ALD process, thus using crystalline silicon. In contrast, Cyclohexasilane deposits an amorphous silicon structure, a-Si, which offers many advantages:
- Can be deposited at lower temperatures, << 400 °C, which allows for a wide variety of substrates, including some plastics for printed electronics.
- a-Si is much less susceptible to mechanical degradation and pulverization; this is especially important in lithium-ion battery applications.
- Another advantage a-Si has in lithium-ion batteries is a higher potential of lithiation (reaction with lithium) which reduces the amount of lithium dendrites (lithium crystals formed on electrode surfaces). Suppression of dendrites improves battery safety and cycle life.
- a-Si has a lower manufacturing cost.
- In photovoltaic applications a-Si has better blue light absorption and superior thermal properties which leads to a lower cost of produced electricity.
Currently, the widespread adoption of a-Si as a material is limited by the commercial availability of a suitable silicon precursor. One such precursor that enables low-temperature a-Si growth is cyclohexasilane (CHS). CHS not only produces a-Si at the lowest temperature of any known polysilane, but does so with growth rates that are much higher.
The Coretec Group is commercializing Cyclohexasilane because it builds upon existing silicon anode manufacturing processes, with better deposition characteristics, lower cost, and lower temperatures, while delivering better quality.