高周波支援マグネトロンスパッタリング法におけるAr^+及びTi^+のエネルギー分布のコイル自己バイアス依存性 Dependence of Ar^+ and Ti^+ Ion Energy Distribution on dc Self Bias of the rf Inductive Coil in Inductively-coupled rf Plasma Enhanced Magnetron Sputtering
Energy distribution of Ar<SUP>+</SUP> and Ti<SUP>+</SUP> ions and plasma conditions have been examined for various dc potentials of the rf coil in inductively-coupled-rf-plasma enhanced magnetron sputtering. The cathode used in the experiment was a conventional type magnetron cathode coupled with an rf coil (60 mmφ, made of Cu). The energy distributions of ions have been measured by an energy-resolved mass spectrometer (Balzers Type PPM42). The plasma conditions have been measured by a triple-probe-type plasma monitor. The coil dc potential was controlled by varying the resistance of the resistor in the termination LCR circuit connecting the coil to the ground. By increasing the resistance of the LCR circuit, the peak of the Ar<SUP>+</SUP> energy spectra shifted from about 175 eV for the termination resistance of 0 Ω (the coil was grounded) to about 75 eV for the resistance of 1.3 kΩ. In addition, it is found by the probe measurements that the plasma potential decreased from 175 to 80 V with increasing the termination resistance. It is interpreted that both variations of ion peak energies and plasma potential well coincided; as a result of the vary in the plasma potential, the energy distribution of ions accelerated toward the grounded substrate by the sheath shifts to a lower energy in accord with a plasma potential vary. The results obtained suggest that the coil potential affected the plasma potential as well as the energy distribution of ions incident to the electrically grounded substrate through the plasma sheath.
真空 42(3), 409-412, 1999-03
The Vacuum Society of Japan