Optical emission studies and neutral stream characterization of a surface reflection materials processing source

Abstract

We report optical emission studies of the plasma source and measurements using heat flux and momentum analyzers of the fast neutral flux and energy in a low-energy surface-reflection neutral source. Both optical emission and Langmuir probe studies indicate a mode transition from a capacitively coupled mode to an inductively coupled mode as the rf power is increased. Spectroscopic actinometry shows that the atomic species resulting from molecular dissociation increase with increasing rf power. Changing the reflector bias changes the neutral energy without changing the discharge composition. The measured heat flux and momentum carried by the fast neutrals are used to derive the flux-weighted average velocity and the particle flux of the neutral stream. The measured neutral stream energy is found to be 4–6 eV. The neutral flux increases with the rf power. The measured neutral energy increases less than linearly with the reflector bias. This might be caused by the decreasing reflection efficiency of the reflector plate or a large collisional loss as the neutrals traverse the process region. The etch rates and cleaning rates calculated from the measured neutral flux and previously reported measured ashing and cleaning rates are in good agreement.

Mode transitions in low pressure rare gas cylindrical ICP discharge studied by optical emission spectroscopy

“…By representing the maximum and minimum values of I 811.53 /I 750.51 on figure 10, it is possible to estimate that the electron temperature in the H-mode varies between 0.8 eV at a low injected power (30 W) and 1.7 eV at a high injected power (110 W). The estimated electron temperatures agree with the values of Tang and Manos [10] and also with our TRG-OES measurements (section 3).…”

“…In the H-mode, they found 2 × 10 12 n e 10 13 cm −3 and 2 T e 2.5 eV. Tang and Manos [10] have reported electron temperature results obtained by double-probe measurements in a similar apparatus. They have also found a decrease in T e from 4-5.5 eV in the E-mode to 1.5-2.5 eV in the H-mode at 200 W and 7 mTorr.…”

“…This was noticed for the first time by MacKinnon [9]. At low input rf powers and a low electron density, the discharge operating in the E-mode is characterized by relatively low optical emission, and a low electron density and high electron temperature [10]. The electrostatic field is larger than the induced electrical field and it maintains the plasma.…”

“…The electrostatic field is larger than the induced electrical field and it maintains the plasma. At higher input power, the discharge operating in the H-mode is characterized by an intense optical emission and high electron density [10]. In addition, the electron energy distribution function (eedf ) can also change in the E-to-H-mode transition.…”

Effect of spheroidized microstructure on the impact toughness and electrochemical performance of a high‐carbon steel

“…It is important to mention here that the diffusion of C atoms is highly governed by the variation in the radius of curvature of the kink, which creates a difference in the chemical potential, thereby encouraging diffusion. [ 12,13 ] Considering the fact that the diffusion process is accelerated with the rise in the annealing temperature and time, a greater duration of annealing time in the WR873K‐2H specimen has helped it to attain a near‐complete spheroidized microstructure (see Figure 1c). Moreover, this uniform dispersion of cementite spheroids in the WR873K‐2H specimen (see Figure 1c) is known to pin the grain boundaries (Zener drag effect) and obstruct their mobility during the annealing treatment, thus limiting the ferrite grain size to the ultrafine range, as reported in our previous communication.…”