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Secondary ion beam profile calculations in a 252Cf plasma desorption time-of-light mass spectrometer
Classified abstracts 7073-7080 over the range of parameters studied. The measured distributions were fitted to a function of the form g(E) = ax/Eex p ( - b E g) and a compilation of 18 data sets yielded a value of x = 1.53+0.07, whereas Maxwellian distributions would have yielded x = 1. The average electron energies from the measure distributions were in surprisingly good agreement with values from the Langmuir probe electron temperatures. J E Heidenreieh III et ul, J Vac Sci Technol, B6, 1988, 288-292. 41 7073. An JsO study of oxygen exchange phenomena during microwavedischarge plasma oxidation of silicon The mechanism of oxygen migration during microwave-discharge plasma oxidation of Si is investigated using secondary ion mass spectroscopy depth-profile analysis and ~80 as a tracer. The exchange phenomenon between migrating oxygen and its counterpart in SiO2 is observed. When the plasma-grown oxide (Si1602) is reoxidized in 180 plasma, the ~sO is observed both at the Si/SiO2 interface and in the bulk of the Si~602. In a reverse example, when Sil802 is reoxidized in 160 plasma, the total amount of pre-existing ~80 in Si1802 decreases. The suppression of 180 is more distinct near the surface region. These oxygen distributions indicate that oxygen migrates toward the interface accompanied by oxygen exchange. Since the exchange phenomenon is not observed in dry thermal oxidation, in which oxygen molecules migrate, active oxygen atoms or atom ions should induce the exchange by breaking the Si-O bond during migration. Shin-iehiro Kimura et al, J appl Phys, 63, 1988, 46554660. 41 7074. Magnetic field gradient effects on ion energy for electron cyclotron resonance microwave plasma stream The effects of mirror field application on ion energy and its dispersion for electron cyclotron resonance (ECR) microwave plasma stream are discussed. Low-energy ions with minimal dispersion are extracted from ECR microwave plasma in the mirror field. Mirror field effects on the ion energy profile are caused by a decrease in plasma microparameter distribution, including plasma potential, electron temperature and plasma density. A highly dense ion stream is extracted from ECR plasma with the mirror field. Morito Matsuoka and Ken'ichi Ono, J Vac Sci Technol, A6, 1988, 25-29. 41
7075. Coherent meson production relativistic heavy-ion collision This paper presents a study on the coherent meson production in t2Cemulsion interactions at 4.5 G e V - c - l ' n u c l e o n t incident momentum. The search for coherence was done through noting the shape of the multiplicity distribution in different narrow rapidity bins and observing whether or not the distribution was according to Poisson; when the fields are completely coherent the multiplicity should have a Poisson distribution. It was observed that the multiplicity distribution was Poisson in nature in two bins o f higher rapidity and consequently the field was coherent in those rapidity bins. The percentage of coherent meson production was estimated to be 48%. On pr6sente dans cet article une 6tude sur la coh6rence de la production de m6sons dans les interactions de ~2C dans des 6mulsions, fi 4,5 GeV/c d'impulsion des nucleons incidents. La recherche de la coh6rence a bt6 effectu6e en consid6rant la forme de la distribution de multiplicit6 pour diff6rentes tranches 6troites de rapidit6, et en observant si la distribution est de Poisson ou non ; lorsque les champs sont compl6tement coh6rents, on dolt avoir une distribution de Poisson. On a observ6 une distribution de Poisson pour la multiplicit6 dans deux tranches de plus haute rapidit6 ; les champs sont par cons6quent coh6rents pour ces rapidit6s. Le pourcentage de production coh6rente de m~sons a 6t~ estim~ fi 48%. [Traduit par la revue] Dipak Ghosh et al, Can J Phys, 66, 1988, 26-28.
42 7077. Nondiffusive velocity broadening in ion energy analyzer operation Fluctuations in plasma potential bring about an apparent broadening in the ion energy distribution when it is derived from the F V characteristic of a retarding grid energy analyzer. This effect may have detrimental consequences for the prospects of applying energy analyzers to measure diffusion of the background distribution when electrostatic turbulence is present. The effect is demonstrated by inducing spatially homogeneous oscillations of the plasma potential in a beam-plasma system, applying a directional ion energy analyzer for beam detection. A theoretical analysis is presented, and quantitative agreement with the experimental results is obtained. H Fujlta et al, J appl Phys, 63, 1988, 308-314. 42 7078. Novel approach for particle velocity and size measurement under plasma conditions A novel technique is proposed for the simultaneous, in-flight, measurement o f the velocity and size of individual particles under plasma conditions. The method is based on the observation of each particle through its own emission and the analysis, in the time domain, of the waveform of the light burst generated as it crosses an observation window of known dimensions. A theoretical analysis of the parameters affecting the visibility o f the particles in an argon plasma showed that depending on the particle diameter and its surface temperature, its thermal visibility factor will drop sharply from 1.0 to almost zero, with the increase o f the background plasma temperature. Measurements are carried out using nickel particles (aTp= 78 #m, a = 18.0/tm) injected axially into an inductively coupled rfplasma ( f = 3 MHz, P = 15 kW) operated using argon as the plasma gas at atmospheric pressure and under soft vacuum conditions (p = 760 and 150 Torr). The results are in good agreement with particle velocity data obtained using laser Doppler anemometry. The measured, in-flight, particle size distribution is consistent with optical microscopic measurement of the particle size distribution of the injected powder. Tadahiro Sakuta and Maher I Boulos, Rev Sci lnstrum, 59, 1988, 285 291. 42 7079. Magnetron plasma diagnostics and processing implications Numerous diagnostics have been used to help characterize and understand conventional magnetron plasmas. These include Langmuir probe studies, magnetic measurements of the drift currents, optical measurements of the sheath, along with emission spectroscopy of the sputtered species. The plasma conductivity is described by Bohm diffusion, and the sheaths by Child's law. Local gas density measurements in the nearcathode region show significant reductions in the gas density as a function of discharge current. The plasma in a magnetron is strongly perturbed by the energetic sputtered species. The plasma impedance as a function of current is significantly altered by the magnitude and energy of the sputtered species, as well as the gas cross section and velocity. This effect has been modeled in terms of the energetic sputtered atom flux into the plasma region and the thermal conductivity o f the gas. Deposition measurements on the cathode itself document the effects of gas scattering and the density modification due to the heating by the sputtered flux. The gas rarefaction effect modifies the energetic particle bombardment of the film in a nonlinear way with rate. It modifies the effective energy transferred to a film with each depositing atom, and alters the transition of elemental targets to the compound form when sputtering in a reactive atmosphere. S M Rossaagei, J Vac Sci Technol, A6, 1988, 1821-1826.
V. Analysis of materials and surfaces 42. PLASMA DIAGNOSTICS 42 7076. Secondary ion beam profile calculations in a 252Cfplasma desorption time-of-light mass spectrometer Calculations of the secondary ion beam profiles properties in a 252Cf plasma desorption mass spectrometer were carried out. The influence of different experimental factors was discussed. A comparison with experimental results is also reported. F Riggi, Nucllnstrum Meth Phys Res, B31, 1988, 588-591. I000
50. R U T H E R F O R D BACKSCATTERING A N D N U C L E A R REACTIONS 50 7080. Characterization of the sifieon-on-insulator material formed by highdose oxygen implantation using spectroscopic elfipsometry Nondestructive characterization of high-dose oxygen implanted and 1350°C annealed silicon-on-insulator structures has been performed by spectroscopic ellipsometry. This method provides a fully in-depth profiling (thickness and nature) of the structure including interfaces. Results
7075. Coherent meson production relativistic heavy-ion collision This paper presents a study on the coherent meson production in t2Cemulsion interactions at 4.5 G e V - c - l ' n u c l e o n t incident momentum. The search for coherence was done through noting the shape of the multiplicity distribution in different narrow rapidity bins and observing whether or not the distribution was according to Poisson; when the fields are completely coherent the multiplicity should have a Poisson distribution. It was observed that the multiplicity distribution was Poisson in nature in two bins o f higher rapidity and consequently the field was coherent in those rapidity bins. The percentage of coherent meson production was estimated to be 48%. On pr6sente dans cet article une 6tude sur la coh6rence de la production de m6sons dans les interactions de ~2C dans des 6mulsions, fi 4,5 GeV/c d'impulsion des nucleons incidents. La recherche de la coh6rence a bt6 effectu6e en consid6rant la forme de la distribution de multiplicit6 pour diff6rentes tranches 6troites de rapidit6, et en observant si la distribution est de Poisson ou non ; lorsque les champs sont compl6tement coh6rents, on dolt avoir une distribution de Poisson. On a observ6 une distribution de Poisson pour la multiplicit6 dans deux tranches de plus haute rapidit6 ; les champs sont par cons6quent coh6rents pour ces rapidit6s. Le pourcentage de production coh6rente de m~sons a 6t~ estim~ fi 48%. [Traduit par la revue] Dipak Ghosh et al, Can J Phys, 66, 1988, 26-28.
42 7077. Nondiffusive velocity broadening in ion energy analyzer operation Fluctuations in plasma potential bring about an apparent broadening in the ion energy distribution when it is derived from the F V characteristic of a retarding grid energy analyzer. This effect may have detrimental consequences for the prospects of applying energy analyzers to measure diffusion of the background distribution when electrostatic turbulence is present. The effect is demonstrated by inducing spatially homogeneous oscillations of the plasma potential in a beam-plasma system, applying a directional ion energy analyzer for beam detection. A theoretical analysis is presented, and quantitative agreement with the experimental results is obtained. H Fujlta et al, J appl Phys, 63, 1988, 308-314. 42 7078. Novel approach for particle velocity and size measurement under plasma conditions A novel technique is proposed for the simultaneous, in-flight, measurement o f the velocity and size of individual particles under plasma conditions. The method is based on the observation of each particle through its own emission and the analysis, in the time domain, of the waveform of the light burst generated as it crosses an observation window of known dimensions. A theoretical analysis of the parameters affecting the visibility o f the particles in an argon plasma showed that depending on the particle diameter and its surface temperature, its thermal visibility factor will drop sharply from 1.0 to almost zero, with the increase o f the background plasma temperature. Measurements are carried out using nickel particles (aTp= 78 #m, a = 18.0/tm) injected axially into an inductively coupled rfplasma ( f = 3 MHz, P = 15 kW) operated using argon as the plasma gas at atmospheric pressure and under soft vacuum conditions (p = 760 and 150 Torr). The results are in good agreement with particle velocity data obtained using laser Doppler anemometry. The measured, in-flight, particle size distribution is consistent with optical microscopic measurement of the particle size distribution of the injected powder. Tadahiro Sakuta and Maher I Boulos, Rev Sci lnstrum, 59, 1988, 285 291. 42 7079. Magnetron plasma diagnostics and processing implications Numerous diagnostics have been used to help characterize and understand conventional magnetron plasmas. These include Langmuir probe studies, magnetic measurements of the drift currents, optical measurements of the sheath, along with emission spectroscopy of the sputtered species. The plasma conductivity is described by Bohm diffusion, and the sheaths by Child's law. Local gas density measurements in the nearcathode region show significant reductions in the gas density as a function of discharge current. The plasma in a magnetron is strongly perturbed by the energetic sputtered species. The plasma impedance as a function of current is significantly altered by the magnitude and energy of the sputtered species, as well as the gas cross section and velocity. This effect has been modeled in terms of the energetic sputtered atom flux into the plasma region and the thermal conductivity o f the gas. Deposition measurements on the cathode itself document the effects of gas scattering and the density modification due to the heating by the sputtered flux. The gas rarefaction effect modifies the energetic particle bombardment of the film in a nonlinear way with rate. It modifies the effective energy transferred to a film with each depositing atom, and alters the transition of elemental targets to the compound form when sputtering in a reactive atmosphere. S M Rossaagei, J Vac Sci Technol, A6, 1988, 1821-1826.
V. Analysis of materials and surfaces 42. PLASMA DIAGNOSTICS 42 7076. Secondary ion beam profile calculations in a 252Cfplasma desorption time-of-light mass spectrometer Calculations of the secondary ion beam profiles properties in a 252Cf plasma desorption mass spectrometer were carried out. The influence of different experimental factors was discussed. A comparison with experimental results is also reported. F Riggi, Nucllnstrum Meth Phys Res, B31, 1988, 588-591. I000
50. R U T H E R F O R D BACKSCATTERING A N D N U C L E A R REACTIONS 50 7080. Characterization of the sifieon-on-insulator material formed by highdose oxygen implantation using spectroscopic elfipsometry Nondestructive characterization of high-dose oxygen implanted and 1350°C annealed silicon-on-insulator structures has been performed by spectroscopic ellipsometry. This method provides a fully in-depth profiling (thickness and nature) of the structure including interfaces. Results