Inductively coupled plasma (ICP) is a promising low pressure, high density plasma source for material processing and is of great importance to modern plasma technology. This thesis summarizes the results of experimental study in a cylindrical ICP by using a single Langmuir probe (LP) and optical emission spectroscopy (OES). <p>The electron energy distribution function (EEDF), which contains important information of ICP plasma and is necessary for an accurate kinetic description of the low-pressure discharges, has been investigated with the Langmuir probe by using the alternating current (ac) method. Measurements were carried out in different gases including both atomic (argon, helium) and molecular (hydrogen, nitrogen) gases. The effects of the external discharge parameters such as gas pressure and radio frequency (rf) power have been investigated and the different mechanisms that influence the formation of the EEDF have been discussed. The radial dependence of the EEPF in the argon plasma has also been evaluated. <p>The average electron energy and electron density have also been obtained by direct measurement of the electron current-voltage (I-V) curve and the result is consistent with the power balance equation.<p> Optical emission spectroscopy has been used to study the importance of neutral gas heating in the ICP. The method used is based upon simulating and fitting the nitrogen emission band (the transition from,uCΠ30'=V to,gBΠ30"=V). Both nitrogen and argon plasmas have been studied separately and significant neutral heating has been found.

Inductively coupled plasma (ICP) is a promising low pressure, high density plasma source for material processing and is of great importance to modern plasma technology. This thesis summarizes the results of experimental study in a cylindrical ICP by using a single Langmuir probe (LP) and optical emission spectroscopy (OES). <p>The electron energy distribution function (EEDF), which contains important information of ICP plasma and is necessary for an accurate kinetic description of the low-pressure discharges, has been investigated with the Langmuir probe by using the alternating current (ac) method. Measurements were carried out in different gases including both atomic (argon, helium) and molecular (hydrogen, nitrogen) gases. The effects of the external discharge parameters such as gas pressure and radio frequency (rf) power have been investigated and the different mechanisms that influence the formation of the EEDF have been discussed. The radial dependence of the EEPF in the argon plasma has also been evaluated. <p>The average electron energy and electron density have also been obtained by direct measurement of the electron current-voltage (I-V) curve and the result is consistent with the power balance equation.<p> Optical emission spectroscopy has been used to study the importance of neutral gas heating in the ICP. The method used is based upon simulating and fitting the nitrogen emission band (the transition from,uCΠ30'=V to,gBΠ30"=V). Both nitrogen and argon plasmas have been studied separately and significant neutral heating has been found.

The current semiconductor device manufacturing requires more strict control of plasma etching. In this research, plasma etching was investigated through gas phase characterization and interface reactions. Hydrogen and nitrogen were added to Ar plasmas to manipulate the electro-physical properties that were measured by a Langmuir probe system. Hydrogen addition modified the EEDF (electron energy distribution function) by increasing the electrons in high energy range. Adding N2 formed a strong bi-Maxwellian distribution. Gas addition caused the transition between ohmic and stochastic heating. Ar-CH4-H2 and Ar-N2-H2 plasmas were also tested. Hydrogen atom beam was used on porous silicon dioxide based low-k films to remove silanol groups that were generated due to the damage of films during pattern transfer. At H2 atom beam process at 150 C moved close to 60% silanol groups were removed in less than 3 min with an etching rate of 15 A/min. The apparent activation energy was 2.4 kcal/mol. Hydrogen atoms reacted with Si-O-Si and methyl groups. The etching mechanisms of CH4/H2/Ar plasma for InP were analyzed by a beam reactor system. Sputtering yield was measured, threshold energy was approximately 60 eV. Inert ion beam assisted chemical reactions gave higher etching rate. The CH4 concentration had no strong effect on etching rate after 5%. Etching rate was not sensitive to temperature up to 150 C. The adsorption of methyl groups to the surface was proposed as rate limiting step. Chemical reaction effectively reduced the surface roughness.

Le but de cette thèse était d’étudier la dynamique de croissance par pulvérisation par plasma RF magnétron des couches minces à base d’oxyde de zinc destinées à des applications électroniques, optoélectroniques et photoniques de pointe. Dans ce contexte, nous avons mis au point plusieurs diagnostics permettant de caractériser les espèces neutres et chargées dans ce type de plasmas, notamment la sonde électrostatique, la spectroscopie optique d’émission et d’absorption, ainsi que la spectrométrie de masse. Par la suite, nous avons tenté de corréler certaines caractéristiques physiques de croissance des couches de ZnO, en particulier la vitesse de dépôt, aux propriétés fondamentales du plasma. Nos résultats ont montré que l’éjection d’atomes de Zn, In et O au cours de la pulvérisation RF magnétron de cibles de Zn, ZnO et In2O3 n’influence que très peu la densité d’ions positifs (et donc la densité d’électrons en supposant la quasi-neutralité) ainsi que la fonction de distribution en énergie des électrons (populations de basse et haute énergie). Cependant, le rapport entre la densité d’atomes d’argon métastables (3P2) sur la densité électronique décroît lorsque la densité d’atomes de Zn augmente, un effet pouvant être attribué à l’ionisation des atomes de Zn par effet Penning. De plus, dans les conditions opératoires étudiées (plasmas de basse pression, < 100 mTorr), la thermalisation des atomes pulvérisés par collisions avec les atomes en phase gazeuse demeure incomplète. Nous avons montré que l’une des conséquences de ce résultat est la présence d’ions Zn+ suprathermiques près du substrat. Finalement, nous avons corrélé la quantité d’atomes de Zn pulvérisés déterminée par spectroscopie d’émission avec la vitesse de dépôt d’une couche mince de ZnO mesurée par ellipsométrie spectroscopique. Ces travaux ont permis de mettre en évidence que ce sont majoritairement les atomes de Zn (et non les espèces excitées et/ou ioniques) qui gouvernent la dynamique de croissance par pulvérisation RF magnétron des couches minces de ZnO. / The goal of this thesis was to study the growth dynamics of zinc oxide based thin films by RF magnetron sputtering plasmas for advanced electronic, optoelectronic, and photonic applications. In this context, we have developed several diagnostics to characterize neutral and charged species in such plasmas, in particular electrostatic probe, optical emission and absorption spectroscopy, as well as plasma sampling mass spectrometry. Afterward, we have tried to correlate specific physical characteristics of as-grown ZnO thin films, in particular the deposition rate, to fundamental plasma properties. Our results have shown that the ejection of Zn, In and O atoms during the RF magnetron sputtering of Zn, ZnO and In2O3 targets does not significantly influence the number density of positive ions (and thus the electron density assuming quasi-neutrality) as well as the electron energy distribution function (populations of low and high energy). However, the ratio of the number density of metastable argon atoms (3P2) to the electron density decreases with increasing concentration Zn atoms; a feature that can be ascribed to Penning ionization of RF sputtered Zn atoms. Furthermore, over the range operating conditions examined in this study (low-pressure plasmas), the thermalization of sputtered atoms by collisions with atoms in the gas phase remains incomplete. We have shown that one of the consequences of this result is the presence of suprathermic Zn+ ions near the target. Finally, we have correlated the quantity of sputtered Zn atoms determined by optical emission spectroscopy with the deposition rate of ZnO thin films measured by spectroscopic ellipsometry. This set of data lead us to the conclusion that mainly Zn atoms (and not excited and/or ionic Zn species) govern the growth dynamic of ZnO-based thin films during magnetron sputtering in argon RF plasmas.

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