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We developed [Lu.sub.0.4][Gd.sub.1.6]Si[O.sub.5] (LGSO) crystal as a new scintillator for medical imaging applications. The size of the LGSO ingot obtained for this investigation was approximately 60 mm in diameter and 170 mm in length. The as-grown crystal was yellow in color. To eliminate the tint, the crystal was annealed in pure [N.sub.2] atmosphere after the growth. As a result, the LGSO became colorless with uniform and large light output which is about 2.0 times that of GSO. Index Terms--Annealing, LGSO, scintillation properties.

The emission spectra for X-ray and UV excitation, decay curve for emission above 460 nm under [gamma]-ray excitation, and energy spectrum by using avalanche photodiode (APD) for excitation with [sup.137] Cs [gamma]-rays have been measured for [Lu.sub.0.4] [Gd.sub.1.6] Si[O.sub.5] having 2.0 mol% Ce. The emission spectrum under X-ray excitation showed two peaks around 430 and 495 nm. The excitation-emission spectrum under UV excitation also had two peaks at 425 and 510 nm for excitation wavelength of 285 and 385 nm, respectively. There was no significant difference in decay constants of emission between the longer and shorter wavelength components. Energy resolution by using an APD was 8.0% for [sup.137] Cs [gamma]-ray excitation. Index Terms--Emission wavelength, radiation detector, scintillator.

Amorphous SiO2 (a-SiO2) layers were prepared using a thermal oxidation method. The SiO2 layers were nitrided at a temperature Tn between 450 and 650 °C utilizing a plasma generation system, in which the layers before the nitridation were simultaneously grown on two different n-type crystalline Si substrates, one having a high resistivity for electron-spin resonance (ESR) and Fourier transform infrared absorption measurements and another having a low resistivity for current–voltage (I–V) measurement. We found the breakdown strength, estimated based on the I–V characteristics, increased with increasing Tn until 550 °C, but the annealing at a further high Tn caused also a decrease in the breakdown strength. We found a strong correlation between the changes in the I–V characteristics and those in the bonding properties, and this correlation was also discussed in connection with the change in the ESR properties for the a-SiOxNy layers. Furthermore, incorporation of N atoms into SiO2 layers at Tn=550 °C was suggested to improve the structural properties and the electrical properties. [ABSTRACT FROM AUTHOR]

Amorphous silicon oxynitride (a-SiN[sub x]O[sub y]) films were deposited at 300 °C using a plasma-enhanced chemical vapor deposition technique, which was carried out with variation in the nitrogen-flow-rate ratio (R[sub N]) and the oxygen-flow-rate ratio (R[sub O]) to control the nitrogen and oxygen contents, x and y, respectively. Changes in the structural properties and the characteristics of defects in the films were examined based on the electron spin resonance as well as infrared and optical absorption measurements. An increase in either R[sub N] or R[sub O] was found to decrease the deposition rate, the density of charged or neutral defects, and the randomness of the bonding network. Thus the incorporation of O or N atoms into Si nitride or Si oxide films, respectively, acts to improve the qualities of the insulating films. Furthermore, the nearest N and O atom neighboring to a Si site would be randomly bonded to the Si atom. Our results also showed that N-related dangling bonds, other than so-called K centers, are favorably created after annealing, but that the formation of Si-O bonds in the films makes the formation of such defects difficult. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Deals with a study which investigated the electrical and structural properties for the fluorinated silicon oxide (SiO...:F):carbon films in comparison with those for the undoped SiO...:F films. Experimental procedure; Results and discussion.

The structural properties of a-SiO(sub x)N(sub y) layers with different compositions prepared using a plasma nitridation technique for thermally oxidized SiO2 layers by means of current-voltage (I-V), electron-spin resonance (ESR) and Fourier transform infrared spectroscopy (FTIR) measurements is discussed.

Presents a study which examined the bonding properties of glow discharge polycrystalline and amorphous silicon carbide films. Correlation of the growth mechanism and the effects of hydrogen dilution with changes in bonding configuration; Experimental procedure; Results and discussion.

Provides information on a study examining the 200-nm-thick polycrystalline silicon films were deposited by changing the deposition temperature (Td = 150-750...C). Methodology used to conduct the study; Incorporation of O and N atoms depending on Td; Findings of the study.

Provides information on an experiment investigating the structure, optical absorption and photoluminescence (PL) properties of SiOx films subjected to thermal annealing at 750-1100...C. Methodology used to conduct the experiment; Information on Optical absorption; Results of the experiment.