In the development a new horizontal high-current HCD apparatus, optimization of the shape of the magnetic field around the Ta cathode and focusing coils by numerical simulations, and related improvement of the apparatus have been carried out to obtain a continuous coat without abnormal plasma discharges. The strength distribution of the magnetic field of the focusing coils around the Ta cathode plays the most important role for this purpose.
The magnetic field strength at the top of the Ta cathode should be maximum and approximately 1/2 of its value at the center. It is also essential to gradually decrease the strength of the magnetic field from the center of the Ta cathode toward the bottom.
The numerical simulation of the magnetic distribution of the new horizontal high-current HCD apparatus made it possible to maximize the effectiveness of the plasma electron beam and obtain a high evaporation rate without abnormal plasma discharges during the long-term coating.
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