E.K. Lin

Effect of carbon sources on silicon carbon nitride films growth in an electron cyclotron resonance plasma chemical vapor deposition reactor

Abstract The effect of carbon source on SiCN film growth was studied in an electron cyclotron resonance plasma chemical vapor deposition reactor. The growth characteristics of CH4, C2H2 and CH3NH2 were examined with and without H2 addition during growth. The results indicated that SiCN films were deposited successfully using CH4 with H2 addition as well as using CH3NH2 both with and without H2 addition. (Si; C) and N composition ratios of the films thus deposited were around 0.75. Carbon was hardly incorporated into the films when deposited using C2H2 as the source gas regardless of H2 addition during growth. Among the three source gas studied, CH3NH2 was the most effective for the SiCN films growth. Spectroscopic study of the gas phase species during growth and discussion on the growth phenomena are presented in this paper.

L x-ray production in lanthanide elements by 1 - 5 MeV helium ions

L x-ray production in and was measured for bombardment in the energy range 1 - 5 MeV. Very thin target foils were used, and x-ray yields were measured simultaneously with elastically scattered ions. The L-shell and individual and production cross sections and their ratios were extracted. These cross sections are compared to the results of the ECPSSR theory (energy-loss and Coulomb deflection effects, perturbed stationary state approximation with the relativistic correction), its united-atom (UA) extension UA-ECPSSR and the UA-ECPSSR-MI, which also accounts for multiple ionization (MI). With a few exceptions, the standard ECPSSR appears to be better than its modifications when and ratios are analysed. and and total L x-ray production cross sections, however, are in the best overall agreement with the UA-ECPSSR-MI theory.

External-beam PIXE analysis of ancient chinese coins

Abstract The external-beam PIXE (proton induced X-ray emission) method has been applied for the determination of the elemental composition of ancient Chinese coins in the Ching Dynasty (AD 1644–1911). The X-ray emission measurements for the samples bombarded with 3 MeV protons from 9SDH-2 Pelletron tandem accelerator were carried out with the use of a 30 mm 2 × 5 mm Ge(Li) detector. The external-beam milliprobe designed for the experiment is essentially the same as the one used in our previous works. Variations of composition for more than 23 samples covering a time period of about three hundred years were examined. Results on the contents of principal component elements (Cu, Zn, Pb, Sn, Sb, Fe, Ni and As) are presented and discussed.

Hydrogen and deuterium in palladium

Abstract The electrochemical permeation technique has been used to measure the diffusivity and permeability of hydrogen and deuterium in palladium. A discharge technique was also used to measure the solubility of hydrogen and deuterium in palladium. The permeation results showed an Arrhenius temperature dependence of diffusivity and permeability between 298 and 340 K. The solubility values of hydrogen and deuterium in palladium from measurements show an exothemic reaction. Cathodic charging on palladium electrodes was also observed, fusion spectra was not found in our results. The surface morphology and deuterium charged specimen was examined by scanning electron microscope.

PIXE ANALYSIS OF ANCIENT CHINESE CHANGSHA PORCELAIN

Abstract In this work, proton induced X-ray emission (PIXE) method was applied for the analysis of ancient Chinese Changsha porcelain produced in the Tang dynasty (AD 618–907). A collection of glazed potsherds was obtained in the complex of the famous kiln site at Tongguan, Changsha city, Hunan province. Studies of elemental composition were carried out on ten selected Changsha potsherds. Minor and trace elements such as Ti, Mn, Fe, Co, Cu, Rb, Sr, and Zr in the material of the porcelain glaze were determined. Variation of these elements from sample to sample was investigated. Details of results are presented and discussed.

Effect of H2 addition on SiCN film growth in an electron cyclotron resonance plasma chemical vapor deposition reactor

The effect of H2 addition on SiCN film growth was studied in an electron cyclotron resonance plasma chemical vapor deposition reactor. No carbon incorporation was observed in the film by feeding CH4/SiH4/N2 even at CH4∶SiH4 ratios as high as 150∶1. With H2 addition and at a CH4∶SiH4 ratio of 100∶1 and above, the carbon contents within the films increased significantly. Possible explanations for this behavior involve gas phase and surface reactions of hydrogen including formation of active carbon species in the gas phase by hydrogen abstraction reactions and preferential etching of surface-bonded carbons.

Effect of dilution gas on SiCN films growth using methylamine

Methylamine (CH3NH2) was employed with SiH4 to deposit amorphous silicon carbon nitride films due to its easy dissociation as well as containing both carbon and nitrogen elements. The effect of dilution gas, such as H2 ,N 2, Ar and He on the film growth was studied in electron cyclotron resonance plasma chemical vapor deposition (CVD) reactor. At a microwave power of 250 W and a substrate temperature of 700 ◦ C, ternary silicon carbon nitride film has been successfully deposited using He as dilution gas. However, only binary silicon nitride films were formed using dilution gases of Ar, N 2 and H2 but otherwise similar conditions. Characterization of the films using FTIR, XPS and optical emission study of the plasma were employed to study the growth process. Possible explanations and discussion for the growth behaviors of the dilution gases are presented.

Atomic K shell ionization of Mn, Fe, Ni, Cu and Zn by carbon ions

Abstract Yields of the K X-rays and elastic scattering particles induced by carbon ion impact on thin targets of Mn, Fe, Ni, Cu and Zn have been measured simultaneously at incident energies ranging from 3.0 to 9.0 MeV with steps of 0.6 MeV. Experimental K shell X-ray production cross sections are reported and compared to the first-order Born and the ECPSSR theories, as well as to the results of previous measurements. The ECPSSR theory gives results much closer to the experimental data except at low energies, while the first-order Born approximation overestimates the data by more than a factor of 6 at all energies. In addition, the data obtained for the K β K α intensity ratio are presented and discussed.

A PIXE study of vitrification of carnation in vitro culture

PIXE (Proton Induced X-ray Emission) is a well-known method for elemental analyses of specimens in applied studies. In this paper, we report results of an application of PIXE in trace-element analysis of normal and vitrified carnations in vitro culture. Experiments were performed to study the vitrification in connection with the trace elements in carnation tissues. About two hundred PIXE spectra were obtained from seventy samples with an irradiation of 3 MeV protons from the NEC 9SDH-2 Pelletron tandem accelerator. From the PIXE analysis we determined the trace element composition of normal and vitrified carnations. Our results indicate that there is a significant change of K, Ca, Fe and Zn contents in the vitrification process.

Application of PIXE for elemental analysis of ancient Chinese artifacts

Abstract Proton induced X-ray emission (PIXE) is a well-known method for elemental analysis in many different specimens for various applied studies. In this paper, we report an application of PIXE analysis for a series of ancient Chinese coins from the Tang Dynasty to the Ming Dynasty (AD 618–1679). Ninety-six PIXE spectra were obtained from forty-eight samples of the ancient coins with the use of a Ge(Li) X-ray detector. On each sample two spots at different positions on the flat surface were irradiated per run by 3 MeV protons from a NEC 9SDH-2 pelletron tandem accelerator. The principal component elements (Cu, Pb, Sn and Zn) and others (Fe, Sb, Ni and As) were determined for the analyzed coins. Variations in composition with a time span of about one thousand years for the examined coins were observed. The results are presented and aspects of the evolution of Chinese metallurgy in casting coins are discussed.