Dopants for Solar Cell Fabrication

Emulsitone dopant-Silicafilm products are formulated to provide a precise dopant-oxide to Silicon Dioxide matrix for diffusion. The relative density of dopant atoms thereby becomes an input besides temperature and time in the diffusion recipe.

Phosphorus is the preferred dopant atom for capturing energy from sunlight. Phosphorosilicafilm 3 x 1020 is a liquid formulation containing an alcohol soluble Silicon polymer and Phosphorus Oxide. This product yields a glass film with optimum P2O5 to SiO2 matrix for diffusion into P-type monocrystalline or polycrystalline Silicon.

For back-side diffusion of Boron, Borofilm 100 provides Boric Oxide in a carbon polymer matrix. At diffusion temperature, the carbon polymer has evaporated, leaving only Boron atoms in B2O3 to diffuse directly into the substrate. If seeking P-type diffusion into an N-type substrate, use either Borofilm 100 or Borosilicafilm 5 x 1020 (if seeking to control precisely the Boron surface concentration).

Titaniumsilicafilm Type C generates a 750 Angstrom antireflective coating to increase solar cell efficiency. The film has an Index of Refraction of 1.96.

All Emulsitone formulations are low viscosity liquids. The surface concentration is a function of the dopant-oxide to silicon dioxide ratio. Cutting with solvent will not change this ratio, but will dramatically reduce the cost of materials in spraying applications.

Emulsitone can also formulate specialty solutions like a combined Titanium and Phosphorus dopant Silicafilm for one-step topside diffusion. Email, fax or telephone us to discuss your particular requirements.


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