Deposition
| Formula / Notation | Gas → Solid (no liquid phase): ΔH_dep = −ΔH_sub (exothermic) |
|---|---|
| Also Known As | Reverse sublimation, vapour-to-solid transition, desublimation, CVD (in thin film context) |
What is Deposition?
The phase transition in which a substance changes directly from a gas to a solid without passing through the liquid phase. This is the reverse of sublimation. Examples include frost forming on surfaces and snow crystal formation in clouds.
Formula & Notation
Other Names / Synonyms: Reverse sublimation, vapour-to-solid transition, desublimation, CVD (in thin film context)
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The phase transition in which a substance changes directly from a gas to a solid without passing through the liquid phase. This is the reverse of sublimation. Examples include frost forming on surfaces and snow crystal formation in clouds.
Deposition is exploited in chemical vapour deposition (CVD) for semiconductor film growth, in physical vapour deposition (PVD) for coating hard surfaces, in freeze-drying (lyophilisation) of pharmaceuticals, and in the formation of thin-film solar cells and optical coatings.
Surfaces where deposition occurs can become extremely cold (cryogenic hazard). CVD reactors use toxic precursor gases (silane SiH₄, diborane B₂H₆, TEOS) that require specialist gas handling systems and leak detection. Frost accumulation in industrial settings creates slip hazards.
The formula or notation for Deposition is: Gas → Solid (no liquid phase): ΔH_dep = −ΔH_sub (exothermic)