Influence of a phase-locked RF substrate bias on the E- to H-mode transition in an inductively coupled plasma

摘要: The effect of a capacitive radio frequency (RF) substrate bias on the E- to H-mode transition and electron-heating dynamics in low-pressure inductively coupled plasma (ICP) operated hydrogen is investigated by phase-resolved optical emission spectroscopy (PROES) Langmuir probe measurements. inductive power sources are driven at same phase-locked mode with fixed but adjustable phase between them, as well without lock. For both operations, when discharge E-mode, density significantly influenced choice power. This directly affects power: already low values can substantially reduce threshold for transition. coupling strongly dependent them attributed phase-sensitive confinement mechanism highly energetic electrons produced expanding sheaths ICP coil. At higher pressures beam do not interact opposing sheath and, consequently, diminishes. Using phase-unlocked operation reduces overall also results less pronounced effects. In contrast, using electrodes ring-shaped trenches initial energy enhanced, increasing influence RF discharge.