There are several types of vacuum systems used in nanotechnology, each with its own advantages and limitations:
Rough Vacuum: Typically achieved with mechanical pumps, rough vacuums have pressures ranging from atmospheric pressure down to about 1 millitorr. They are usually the first stage in a multi-step vacuum process. High Vacuum: Achieved using turbomolecular or diffusion pumps, high vacuums range from 1 millitorr to 10^-7 torr. These environments are essential for processes like scanning electron microscopy (SEM). Ultra-High Vacuum (UHV): Achieved using ion pumps and cryopumps, UHV conditions have pressures below 10^-7 torr. UHV is crucial for surface science and the study of atomic-scale phenomena.
