Lämpöhöyrystämisellä

Lämpöhöyrystäminen, often translated as thermal evaporation, is a widely used physical vapor deposition (PVD) technique. It involves heating a source material, typically a solid or liquid, in a vacuum or controlled atmosphere to a temperature at which it begins to vaporize. This vapor then travels through the vacuum chamber and condenses onto a substrate, forming a thin film.

The heat source for thermal evaporation can vary. Common methods include resistive heating, where an electric current passes through a filament or boat containing the source material, causing it to heat up and evaporate. Electron beam heating is another effective technique, where a focused beam of electrons strikes the source material, generating intense localized heat. Inductive heating is also employed for certain materials.

The vacuum environment is crucial for thermal evaporation. It minimizes collisions between the vaporized atoms and gas molecules, allowing them to travel unimpeded to the substrate and form a dense, uniform film. The pressure within the chamber can range from high vacuum to low pressure depending on the specific application.

Thermal evaporation is a versatile process used in various industries, including semiconductor manufacturing, optical coatings, and decorative finishes. It is particularly well-suited for depositing metals, alloys, and some oxides. The thickness and properties of the deposited film can be controlled by adjusting parameters such as evaporation rate, substrate temperature, and deposition time. Substrate rotation is often used to ensure uniform film thickness across the entire substrate surface.