2014 年 57 巻 3 号 p. 80-83
Behavior of high energy negative ion in a RF magnetron plasma with insulating oxide target is discussed. High energy O− ions are produced on the target surface and are accelerated by oscillating RF sheath in front of the target. Maximum O− energy that is influenced by the sheath thickness determined by the plasma density varies depending on the target surface position. O− energy distribution shows fine-structure with many peak and valley. Origin of the fine structure is explained by the deceleration of O− by the time-varying sheath potential, i.e., plasma potential in front of the wall.