Experiments and global model of inductively coupled rf Ar/N2 discharges

Abstract

Experiments with a Langmuir probe and optical emission spectroscopy are carried out in inductively coupled rf ͑13.56 MHz͒ Ar/ N 2 discharges at three total pressures of 30, 60, and 110 mTorr, varying the Ar fractions from 50% to 95%. The electron energy probability functions ͑EEPFs͒ measured at all Ar fractions can be approximated using different exponentials in the bulk and high-energy regions, resulting in two temperature approximation of the measured EEPFs. The electron density slightly increases with increasing the Ar fraction at the Ar fractions below 70%, beyond which it relatively abruptly increases. On the other hand, the electron temperatures gradually decrease with the increase in the Ar fraction. The vibrational temperature does not strongly depend on the Ar fraction, whereas the rotational temperature gradually increases with the increase in the Ar fraction. The density of nitrogen atoms remains constant at the Ar fractions below 80%, beyond which it monotonically decreases with increasing the Ar fraction. A global model for electropositive plasma is used in order to investigate the plasma chemistry in Ar/ N 2 discharges assuming the Maxwellian electron energy distribution. The model results are compared with the experimental results, obtaining reasonably good agreement.

SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

“…This may be due to the ionization according to (3) with an onset for appearance at 15.58 eV as well as dissociative ionization according to (4) at 24.34 eV [39][40][41][42] .…”

“…The elevated electron temperatures indicate low plasma densities caused by the temporary change of the target surface chemistry, which in turn causes lowered sputter yields and secondary electron emission yields. As the target power increases the increasing Tes suggest that the N2 molecule may also be activated according to (5) or (6), where dissociation or excitation (electron quenching) prevails 15,[39][40][41][43][44] . Additionally, recombination reactions 45 like…”

Wall loss of atomic nitrogen determined by ionization threshold mass spectrometry

“…The vibrational population can be estimated with a typical vibrational temperature of T vib = 11, 000 K (see Ref. 39 ) to N 2 (vib)/N 2 (X) ∝ exp(−6.3eV /1eV ) = 0.002. For a vibrational level higher than 6.3 eV (v > 26) the relative density is even lower than 0.002.…”

Measurement and modeling of neutral, radical, and ion densities in H2-N2-Ar plasmas

“…As metastables carry potential energy of several eV, in a collision this energy can be transferred to j so that j can dissociate. To assess whether or not metastable argon Ar meta , metastable molecular nitrogen N 2 (A), and the metastables N(D) and N(P ) of atomic nitrogen influence the dissociation of molecules, they are considered in a simplified collisional-radiative model 57,76 . This model takes into account only the most important electronically excited states.…”