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Hysteresis, one of the interesting characteristics of inductively coupled plasmas, takes place due to the nonlinearities of absorbed power or dissipated power [M. M. Turner et al., Plasma Sources Sci. Technol. 8, 313 (1999)]. In this work, the bias power effect on discharge mode transition and its hysteresis is investigated by measuring the antenna coil currents, time-average substrate voltages, electron densities, and electron energy probability functions (EEPFs). The behavior of hysteresis is comparatively analyzed by introducing a global model that considers the evolution of EEPFs and excitation state species (multi-step ionization). In the absence of bias power, a typical hysteresis appears at a gas pressure of 300 mTorr. The measured EEPF evolves from a Druyvesteyn distribution in the E mode to a Maxwellian distribution in the H mode with growing the antenna power from 25 W to 60 W. Interestingly, when a bias power of 30 W is applied to the substrate, the hysteresis vanishes, and the shape of the EEPF is maintained in each mode. The possible factors are considered the diminished changes in total energy loss (reduced nonlinearity of dissipated power) and in power transfer efficiency between E mode and H mode during the mode transition. [ABSTRACT FROM AUTHOR]

A hysteresis loop has been observed during the E–H mode transition in an inductively coupled plasma at high pressures. The cause of the hysteresis has been reported as a nonlinearity of the transferred and dissipated powers due to capacitive coupling, multi-step ionization, the change in the electron energy probability function (EEPF), and so on [M. M. Turner and M. A. Lieberman, Plasma Sources Sci. Technol. 8(2), 313–324 (1999) and H. C. Lee and C. W. Chung, Sci. Rep. 5, 15254 (2015)]. However, when a coil current reduction is considered, the previous interpretation of hysteresis cannot explain the observations in the intermediate pressure region, where the coil current reduction occurs, but hysteresis is not observed. In this work, the E–H mode transition and its hysteresis are discussed in three pressure regions, the low, intermediate, and high pressure regions, whether or not the coil current and the hysteresis are observed. The power transfer efficiency, transferred power, EEPF, and total energy loss are obtained at 10, 100, and 300 mTorr. Hysteresis is only observed at 300 mTorr, and the coil current reduces at 100 and 300 mTorr during the E–H mode transition. The mechanism of hysteresis is explained in a power balance diagram that includes the transferred power and the dissipated power by considering the power transfer efficiency in the E and H modes. In addition, the conditions of hysteresis and coil current reduction are revealed and classified in this work. [ABSTRACT FROM AUTHOR]