摘要 |
In magnetically enhanced sputtering, pulses are applied having a very high instantaneous power, of the order of at least 0.1 kW-1 MW. In such sputtering regions (23) exist in which electrons are trapped by the magnetic field generated by magnets (17) cooperating with the electric field between the anode being part of the wall (5) enclosing the chamber in which sputtering is performed and the cathode which at the same time is the target (9), from which material is to be sputtered. An ionization of the gas in the chamber will then for lower applied power occur preferably in those regions (23) causing a nonuniform erosion of the target (9). For very high power in the pulses or power density in the pulses the gas in said regions and in regions adjacent thereto will enter another state of fully ionization, which considered in energy terms is located above the unwanted state of an electric arc which is formed for a lower supplied power. The region (27) in which this another state exists will be more homogeneous and have a wider extension than the ionized regions (23) produced for a lower supplied power. This results in a more uniform erosion of the target (9) and a more uniform coating of the substrate (13). The high power pulses can also be used in sputtering ion pumps, allowing them to start pumping from moderately low pressures, e.g. in the range of 10-1-10-2 torr.
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