Spatially resolved ground state atomic oxygen density during the mode transition of inductively coupled oxygen plasmas

Local pressure calibration method of inductively coupled plasma generator based on laser Thomson scattering measurement

“…These control factors can sensitively affect the electron density, electron temperature and other physical parameters of ICP, thus profoundly affect the accuracy of production process. Especially important, the local pressure in a low-pressure plasma affects the mean free path of collisions between electrons and neutral particles, which is closely related to local and non-local dynamic characteristics 6 , electron heating and heating efficiency, electron energy distribution 7 and electron density 8 , discharge mode (E or H mode) 9 , 10 and so on. Therefore, the local pressure is a very important external parameter of low-pressure plasma, especially in terms of accuracy control during the plasma process.…”

Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O2 plasma*

“…7, it can be seen that the emission intensities of 750.4 nm and 844.6nm monotonously decrease with increasing the pressure and the O 2 content, which is caused by the decrease of the dissociation rate of oxygen molecule ([O]/[O 2 ]). When increasing the pressure or the O 2 content, [10,41,42] the electrons will lose their energies significantly via inelastic collision with populated background O 2 , and the fraction of the energetic electrons, which can excite O and Ar atom, decreases. According to the previous studies, [43,44] the collisions with the electron and oxygen atom dominate loss processes of the negative ion at low and high pressures, respectively.…”

“…In the H-mode, a plasma exhibits a higher electron density and a stronger optical emission intensity. [4][5][6][7][8][9][10] In other words, as the applied power increases, the discharge experiences a mode transition from the E-mode to the H-mode. In electronegative ICPs, the negative ions influence the species transport, chemical reactions and physical processes, [11,12] which finally leads to changes of etching profile [13] and the deposition film.…”

“…[14,15] Therefore, researches on the E-to H-mode transition in electronegative ICPs have been extensively and intensively carried out. [6,10,16] Wegner et al [6] found that during the E-to H-mode transition in an Ar/O 2 ICP, the current and voltage amplitudes of the coil are increased in proportion, and the phase angle between them stays almost constant in the E-mode, while it decreases slightly in the H-mode. Lee et al [16] investigated the electron energy distribution function (EEDF) during the E-to H-mode transition of an ICP operated in N 2 , and they found that as the power increases, the EEDF evolves from an unusual distribution (with a hole near 3 eV) in the E mode to a Maxwellian distribution in the H mode.…”

“…Lee et al [16] investigated the electron energy distribution function (EEDF) during the E-to H-mode transition of an ICP operated in N 2 , and they found that as the power increases, the EEDF evolves from an unusual distribution (with a hole near 3 eV) in the E mode to a Maxwellian distribution in the H mode. By using a twophoton absorption laser induced fluorescence method, Zeng et al [10] revealed that the ground state atomic oxygen density increases by one order of magnitude during the E-to H-mode transition in an O 2 ICP. By employing space and phase resolved optical emission spectroscopy, Zaka-ul-Islam et al [17] studied three distinct operation modes (E mode, H mode, and E-to H-transition mode) in an O 2 ICP.…”