Emission spectra of copper and argon in an argon glow discharge containing small quantities of hydrogen

Advanced Plasma Processing: Etching, Deposition, and Wafer Bonding Techniques for Semiconductor Applications

“…When these electrons return to their ground state, a photon may be emitted. The color of the plasma is characteristic of the excited gas species, because the photon energy is a function of the electronic structure of the gas molecules and their interactions with surrounding molecules (Hodoroaba et al, 2000). This can be a good diagnostic for incorrect plasma striking conditions or other adverse changes in your plasma.…”

The effects of traces of molecular gases (H2, N2& O2) in glow discharges in noble gases

“…Hodoroaba [12] reported the effect of hydrogen on about 30 lines in the ArI and ArII spectra and Š míd [24] reported the effect of nitrogen on about 12 argon lines, but there has been no detailed study on the possible underlying discharge processes. In general, the effects produced by nitrogen are smaller; hydrogen increases the intensity of ArII lines whilst nitrogen causes a fall; on the other hand, for ArI lines, a fall occurs in all cases with hydrogen; for some lines nitrogen causes increased intensity.…”

“…The intensity of bands in the 2 nd positive system of nitrogen also showed marked nonlinearity with increasing hydrogen concentration. Hodoroaba [12] and Steers [23] both reported very non-linear behaviour for the intensity of the Hαand Hβlines (656.2nm and 486.1 nm, respectively); these lines should not be subject to self absorption. It is clear that for both hydrogen and nitrogen, the degree of dissociation is highly dependent on the discharge conditions.…”

“…Early work by Hodoroaba [12] and others had shown that the addition of hydrogen to argon causes the suppression of Cu II lines excited by charge transfer. This effect also occurs for Fe II lines [23], as shown in figure 9, where lines in the Fe II spectrum with a total excitation energy (TEE) (ionisation energy + excitation energy of the ion)~15.8 eV (Group A) are suppressed.…”

“…Clearly the values obtained for a thin layer might be incorrect. Hodoroaba [12][13][14][15] carried out a detailed study of the effect of hydrogen on the intensity of copper lines, using controlled additions of hydrogen in the range 0-0.6 % H2 v/v. A large number of Cu I, Cu II, Ar I and Ar II lines were selected using a monochromator, and the relation between line intensity and hydrogen concentration measured for each line.…”