Emissionspectroscopic Investigation of Bci₃ Discharges

Abstract

Radiofrequency discharges in neat BCI, exhibit 3 broad molecular emissions with intensity maxima at about 305,350, and 480 nm. The 350 nm system consists of a progression of bands with an average separation of about 130 cm-l. All three emissions have an identical excitation kinetics in pulse discharges and are, therefore, believed to originate from the same emitter. Arguments are given that the emitter might be electronically excited BCI,.The dominant process of BCI(A) formation in neat BCI, at low r.f. power is shown to be direct electron impact excitation of BCI(X). A transient excess population of BCI(AlI7) in BCI,/Ar discharges is explained as due to an energy transfer from argon metastables.

On the spectroscopic detection of neutral species in a low-pressure plasma containing boron and hydrogen

“…Its main advantages in comparison to later methods [52,53,55,56] are: (i) the possibility of taking into account various secondary excitation (stepwise excitation, dissociative recombination, etc) and deactivation processes (collisional quenching, stepwise ionization, etc) [51,57]; and (ii) its ability to work with arbitrary shapes of the EEDF, which is known to be far from Maxwellian in hydrogen-containing discharge plasmas (see, e.g. [7]). The necessity for absolute spectroscopic and Langmuir probe measurements is its main disadvantage.…”

“…Only a limited number of studies using the spectroscopic approach for boron containing plasmas can be found in the literature. Breitbarth and Ducke used optical emission spectroscopy (OES) to study excitation channels using intensity-time functions of selected emissions in the active phase and the afterglow of the pulsed RF discharge in BCl 3 and BCl 3 -Ar [7]. Schaffnit et al [14] utilized a RF discharge in BCl 3 -N 2 -H 2 -Ar mixtures for BN coating by PECVD.…”

On the Reaction Kinetics of Chemically Active Molecular Microwave Plasmas

“…The spectroscopic determination of the degree of dissociation of hydrogen in non-equilibrium plasmas was first reported in [9][10][11] and further developed in [12][13][14][15][16]. Recently it was shown that an account of the fine structure in balance equations is very important for the calculation of emission rate coefficients of direct and dissociative excitation of H α and H β lines [17].…”

Kinetics of boron atoms in Ar- flowing microwave discharges

“…This process was found to be very efficient in low-pressure (10-40 Pa) r.f. discharges where BCl 3 degree of decomposition is low [13].…”

“…A discussion on B 2 band emission is reported in [5] with new observed transitions from this molecule. Atomic boron lines (λ = 208.9 and 249.7 nm) which are currently used to characterize BCl 3 plasma [11][12][13][14] cannot be detected with our OES arrangement. As concerns the three unidentified transitions (λ = 563.5 nm, 581.9 nm and 582.2 nm) reported in our previous study of this Ar-BCl 3 microwave plasma [5], the line at λ = 563.5 nm is now assigned to the 4p 2 P 0 → 3s 2 S transition of atomic boron.…”