What is considered high vacuum?

High vacuum is generally defined as a pressure range between 10⁻³ and 10⁻⁷ mbar (or 10⁻³ to 10⁻⁶ Torr). This range is significantly lower than atmospheric pressure and is crucial for various industrial and scientific applications.

Here’s a more detailed breakdown:

Pressure Range:
High vacuum is characterized by pressures below 10⁻³ mbar and typically extending down to 10⁻⁷ mbar.
Applications:
High vacuum is used in various fields, including:
Material Science: In thin-film deposition and surface analysis techniques, high vacuum helps ensure a clean environment and minimize unwanted interactions between the material being processed and residual gases.
Electronics Manufacturing: High vacuum is essential for processes like semiconductor fabrication, where even trace amounts of contaminants can affect device performance.
Space Simulation: High vacuum chambers are used to simulate the space environment for testing spacecraft and materials.
Relationship to Ultra-High Vacuum (UHV):
Ultra-high vacuum (UHV) is a further refinement of high vacuum, characterized by even lower pressures, typically below 10⁻⁷ mbar. UHV systems require more specialized equipment and techniques to achieve and maintain such low pressures.
Measurement:
High vacuum pressures are typically measured using specialized gauges that rely on ionization of residual gases or thermal conductivity measurements.
Pumping Systems:
Achieving high vacuum often involves a combination of different pumping techniques. Mechanical pumps are typically used to achieve rough vacuum, which then serves as a backing pressure for higher-performance pumps like turbomolecular pumps that can reach the high vacuum range.