Physical Properties & Nanomaterial Growth

The Coretec Group's Cyclohexasilane™

Cyclohexasilane Details

Cyclohexasilane Vapor Pressure
as a Function of Temperature

Bond Enthalpy Comparison

Aerosol Assisted CVD of Si Thin Films

AA-APCVD Characteristics:
  • Aerosolized liquid precursor
  • Atmospheric pressure
  • Continuous and scalable (R2R)
  • High deposition efficiency at lowthermal budget
Liquid Precursor Formulations For:
  • Intrinsic silicon
  • n and p doped silicon
  • Low K dielectrics (SiOCN)
  • Si-C compositions 
  • SiNx

Deposition rates and activation energies of hydrosilanes (Si6H12 has lowest Ea of known silanes)

Comparison Of Si Film Deposition Techniques

Control of Surface Chemistry & Crystallinity

Solution/Emulsion Polymerization

CHS spontaneously or inductively forms nano-sized domains in select liquid systems such as microemulsions which can be processed to generate silicon nanostructures. Generation of these nanostructures is enabled by the ability to transform CHS intostructurally robust polysilane colloids at RT using UV irradiation or chemical initiators.

SEM image of polysilane colloids generated by
micro-emulsion polymerization of Si6H12 using UV irradiation.

SEM image of a-Si colloids generated by
micro-emulsion polymerization of Si6H12 and heat treatment at 400 °C.

Electrospun Si NWs from CHS-Based Inks

Potential for New Copolymer Physical Chemistry

Advantages of Si6H12 as a PECVD precursor

1. CHS molecule consists of 6 Si atoms which can be simultaneously delivered intothe PECVD chamber thus enabling higher deposition rate compared to traditionalmonosilane.
2. Our experiments have shown that good quality a-Si:H films can be fabricated. Thisfinding allows to partially eliminate a costly multistage purification process, thusmaking CHS a more cost efficient precursor than traditional silanes.
3. CHS has a low vapor pressure at room temperature (0.3 torr), which makes alloperations with this precursor much safer than similar operations withgaseous silanes.
4. CHS does not require any dilution when used (gaseous silanes are diluted with He).This characteristic significantly widens Si delivery and hydrogen dilution ranges.