Measurement of oxygen atom density employing vacuum ultraviolet absorption spectroscopy with microdischarge hollow cathode lamp

Abstract

Articles you may be interested inDevelopment of measurement technique for carbon atoms employing vacuum ultraviolet absorption spectroscopy with a microdischarge hollow-cathode lamp and its application to diagnostics of nanographene sheet material formation plasmas Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation Rev. Sci. Instrum. 79, 093305 (2008); 10.1063/1.2987689 Development of vacuum ultraviolet absorption spectroscopy technique employing nitrogen molecule microdischarge hollow cathode lamp for absolute density measurements of nitrogen atoms in process plasmas Determination of fluorine atom density in reactive plasmas by vacuum ultraviolet absorption spectroscopy at 95.85 nm Rev. The compact measurement system for absolute density of oxygen ͑O͒ atom has been developed, which employs a vacuum ultraviolet absorption spectroscopy ͑VUVAS͒ technique with a high-pressure microdischarge hollow cathode lamp ͑MHCL͒ as a light source. The influences of self-absorption, emission line profile of the MHCL, and background absorption of oxygen molecule (O 2 ) on the determination of absolute O atom density were taken into consideration. This system has been applied for measuring absolute O atom densities in an inductively coupled O 2 plasma. O atom densities were estimated to be on the order of 1ϫ10 12 -1ϫ10 13 cm Ϫ3 at an input power of 100 W and an O 2 pressure ranging from 1.3 to 26.7 Pa. The behavior of O atom density measured using VUVAS technique was consistent with that obtained by actinometry technique using O emission intensities of 844.6 nm and 777.4 nm lines. Moreover, the lifetime of O atom in the afterglow plasma has been measured. The decay curves of the O atom density were fitted with exponential functions. The extinction process of O atom in the inductively coupled O 2 plasma has been discussed.

Influence of plasma chemistry on oxygen triplets

“…The conclusion of this work is that there are regions of operational space where the unresolved 777 oxygen line can be used as a substitute for the real oxygen actinometric line (777.417 nm) [20] but care must be taken. We demonstrate that the upper energy level of the 777 oxygen spectral lines can also be populated by cascade radiative emission from other oxygen triplets (e.g.…”

Investigation of the radially resolved oxygen dissociation degree and local mean electron energy in oxygen plasmas in contact with different surface materials

“…Previous investigations have sought insight into these processes by measuring the density of atomic oxygen and its surface recombination probability for various materials using twophoton absorption laser-induced fluorescence (TALIF), 12,[26][27][28][29][30] optical emission spectroscopy (OES), 21,22,[31][32][33][34] and VUV absorption spectroscopy. 23,35,36 TALIF and VUV absorption are well known for their accuracy, however, both are challenging to implement in industrial plasma reactors, particularly if spatially resolved measurements are required. Optical emission spectroscopy on the other hand has the advantage of being completely non-invasive and easily allows for spatially resolved measurements which are key for understanding radial variations in plasma parameters which are important for uniformity in processing applications.…”

Effect of humidity conditions on active oxygen species generated under ultraviolet light irradiation and etching characteristics of fluorocarbon polymer

“…In such processes, it is important to control the density of the active oxygen precisely. Measurement of active oxygen species in ambient atmosphere requires specialized and high-cost equipment typically incorporating an optical laser system [1] or a vacuum ultraviolet (UV) light source [2,3]. A simple method for real-time sensing such species using reasonably priced equipment is not currently available.…”