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Undoped amorphous-Si (a-Si) films are deposited as a function of deposition temperature on fused quartz substrates by low pressure chemical vapor deposition using 100% disilane. The texture of these poly a-Si films is significantly influenced by the deposition temperature of the initial films which serve as the substrates. The films grown below a temperature of 530 degrees Celsius exhibit a dominant (100) texture and beyond this temperature, a (111) texture. A decrease in deposition temperature results in a reduction of the nucleation rate.

A plasma-enhanced chemical vapor deposition method facilitates the deposition of undoped polycrystalline Si (poly-Si) as a function of rf power and deposition temperature using disilane. A shift in the surface-diffusion coefficient of (SiH)n adsorbates and ion bombardment effects result in a change in texture. The x-ray relative intensity and crystallinity of the poly-Si films decreases with decrease in film thickness. Increase in rf power or thickness favor formation of a low-angle grain boundary rather than an amorphous-like structure.

SiH4-NH3-H2 mixtures facilitated plasma-enhanced chemical vapor deposition of amorphous SiNx:H (a-SiNx:H) films at 300 degrees centigrade. The amorphous films revealed low intrinsic stress, high break-down strength and low buffered HF (BHF) etch rate, when RH and rf power values increased. Such films were used as passivation layers and gate insulators in thin-film transistors. The relaxation of intrinsic stress is due Si-NH-Si bond formation.

The correlation between the stress and bonding characteristics of amorphous hydrogenated SiNx thin films deposited on single crystal Si was investigated using a modified random bonding model. The results showed that intrinsic stress was responsible for the measured tensile stress infilms with an N content higher than 1.0. The incorporated NH bonds induced the intrinsic stress to relax.

The effect of phosphorous and nitrogen doping of polycrystalline SiC films prepared by plasma-enhanced chemical vapor deposition was investigated. The results showed that phosphorous and nitrogen doping of the SiC films enhanced the crystallinity of the material. However, high doping conditions resulted in a deterioration in the crystallinity. In addition, resistivity and dangling-bond density decreased as the crystallinity was enhanced.

X-ray diffraction and x-ray photoelectron spectroscopy were used to investigate the bonding characteristics of glow-discharge polycrystalline and amorphous Si-C films. The results showed that crystallization accompanied some degree of segregation of carbon atoms in grain boundaries. Bonds were observed in high carbon films, and this resulted in a compressive strain.

Undoped polycrystalline films were deposited from a SiH4-H2 mixture by a plasma-enhanced chemical vapor deposition method. Changingpreparation conditions influence the preferential orientation to a random, (100) or (110) crystal axis. Electron spin resonance and the dependence of dark conductivity on measurement temperature have been examined to determine how the structure of the grain boundary depends on the preferential orientationand affects the electrical properties.

A Ce doped [Gd.sub.2]Si[O.sub.5] (GSO) single crystal is an excellent scintillator featuring a large light output, a short decay constant and a high absorption coefficient. It was shown in our previous studies that the surfaces of the scintillator should be polished to get scintillation light output efficiently especially for long and narrow scintillators. Therefore, we newly developed a chemical process to polish the GSO crystal. The surface of the GSO crystal was found to become smooth when it was etched using anhydrous orthophosphoric acid at 150-300 [degrees] C. The process was also proved to be applicable to large size crystal such as 20x20x200 [mm.sup.3] preventing thermal shock crack. An improvement in the scintillator efficiency was confirmed using the chemical polishing process.

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]

ACe doped [Gd.sub.2]Si[O.sub.5] (GSO) single crystal is an excellent scintillator featuring a large light output, a short decay constant and a high absorption coefficient. We have investigated dependence of the scintillation characteristics on the growth atmosphere. GSO crystal is usually grown in pure [N.sub.2], which due to thermal etching during the growth always roughens the boule surface, inducing some micro-cracks on the surface which often triggers the large crack in the boule. To eliminate this, we first introduced 1 vol% [O.sub.2]-containing [N.sub.2] gas for the growth atmosphere. The resultant boule turned be very smooth in surface, but pale yellow in color and degraded in the scintillation characteristics. To retain these properties, we then introduced an annealing process and found the annealing under pure [N.sub.2] atmosphere quite effective on the recovery both in color and scintillation properties.

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.

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.

Presents a study that investigated the effects of the incorporation of phosphorus and nitrogen impurities on the electrical and structural properties of polysilicon carbide thin films. Methodology; Examination of the resistivity and spin density of the samples; Analysis of the crystallinity of the samples.

Presents information on a study which discussed changes of the structural and electrical properties brought about by an in situ plasma supply during growth of undoped and boron doped low-pressure chemical vapor deposition poly-silicon film and plasma-enhanced chemical vapor deposition films. Structural property; Effects of plasma supply on improvement of the surface roughness; Electrical property.

Presents information on a study which analyzed the effects brought about by the addition of nitrogen on the bonding properties as a function of the degree of crystallization for boron-doped microcrystalline into amorphous silicon nitride[subx]:hydrogen films. Investigation of the degree of crystallization by means of x-ray diffraction; Vibrational-absorption profiles; Electrical and optical properties.

Presents a study of the crystal structure and the bonding configurations of Si[sub1-x]C[subx] films prepared by plasma-enhanced chemical vapor deposition. Description of cubic silicon carbide; X-ray diffraction pattern on the films; Classification of films according to the composition.