Diagnostics and analyses of a laser produced organic vapor plasma

摘要

Summary form only given. A fast Langmuir probe technique isdeveloped for diagnosing a plasma produced by a 193 nm laser ionizing anorganic vapor, tetrakis(dimethyl-amino)ethylene (TMAE). The plasma ischaracterized as high electron density (10¹³-10¹²cm^-3), low electron temperature (~0.1 eV). A probe theory oncorrection of sheath motion effects on ion saturation currents inLangmuir probe measurements is developed, and validity conditions arealso presented. Correction factors for sheath motion effect arecalculated for wide ranges of electron-ion recombination coefficients,electron densities, electron temperature changes, plasma potentials andbias voltages. The calculation results can be directly applied for thecorrection of the sheath motion on Langmuir probe measurements. Langmuirprobe electron saturation current method provides a direct electrondensity measurement, which is independent of ion species. The ratio ofelectron and ion saturation current from Langmuir probe and opticalemission experiment can confirm that the major species in theexperiments has not been changed. The optical emission is also carriedout for diagnosing can enhance the delayed emission spectra from TMAEplasma. The plasma decay mechanisms are studied, and a delayedionization process is found to be important. A model is developed tocalculate the lifetime of the delayed ionization which is dependent ofTMAE pressure and electron density