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The studies were conducted to assess the structural evolution and nucleation of Si-nanocrystal in silicon-rich silicon oxide films produced by PECVD (plasma enhanced chemical vapor deposition), as a function of the annealing temperature. The findings reveal the active role played by the hydrogen and nitrogen atoms in the formation of Si-nc and in the thermally induced evolution of the deposited films.

The structural properties of [Mn.sub.x][Ge.sub.1-x] ion implanted alloys at 240 and 270 degree Celsius are studied using X-ray diffraction, transmission electron microscopy, extended X-ray absorption fine structure spectroscopy, and X-ray photoemission spectroscopy. The average efficiency of Mn dilution of ion implantation technique is found to be 50%, which reached a peak value of 100% in the subsurface implanted layer.

The F control of the point defect density in preamorphized Si layers is studied by investigating the F incorporation process during the solid phase epitaxy (SPE) of amorphous Si layers. The results have demonstrated F to be a versatile and powerful tool to control the point defect density in Si, acting as a trap for the Is and indirectly modifying the diffusivity of dopants.

A scanning capacitance microscopy (SCM) was carried out in the angle beveling configuration on B doped, very narrow quantum wells (QWs) of Si0.75Ge0.25 layers strained between Si films. The results showed that a spatial SCM resolution of at least 5 nm was demonstrated on angle beveled samples, not only in terms of signal sensitivity, but also in terms of quantitative majority carrier profiling.

O:Er concentration effects on structural, electrical and optical properties of Si:Er:O layers are examined.

Study of oxygen interaction with Al, Si or P ion implantation-induced defects in Czochralski silicon wafers reveals that oxygen precipitation in Al implanted samples is more than that in Si or P implanted samples and is consistent with maximum accumulation of nuclear energy. Al atom gettering by the silicon dioxide precipitates occurs on the silicon wafers. A growth and nucleation model for SiO2 precipitates and Al segregation is proposed.

Determination of electrical and optical properties of Er-implanted Si shows that electrical activation can be increased by doping Si with oxygen or carbon. Presence of oxygen precipitates distorts the process of luminescence in the oxygen doped samples. Carbon doped samples reveal an enhancement in photoluminescence intensity. Residual defects are low in carbon-doped samples. Oxygen doped and carbon doped Si show variations of intensity ratio of the main photoluminescence peak.

The three-dimensional concentration profiles of ion-implanted Au, Pt and Zn in crystalline silicon were investigated. The results showed that the lateral spread under the mask was bigger than the vertical diffusion, especially on the side opposite to the implanted diffusion source. The features of the measured profiles were brought about by the kick-out mechanism of diffusion for the transition metals.

Epitaxial realignment of polycrystalline Si films was analyzed in terms of structural and kinetic characteristics. The results showed that the realignment mode and the kinetic activity of the process was connected to the microcrystalline structure of the layers, to the morphology of the film and to the presence of As atoms. In addition, the kinetics of the realignment modes were observed to be thermally activated.

A combination of the magnetron sputtering and plasma enhanced chemical vapor deposition techniques is employed for the characterization of the different Si:O alloys. The various parameters that are employed for determining the light absorption and the electrical transport properties of these alloys are also discussed.

The application of the pulse laser annealing technique for the high-level incorporation of antimony in substitutional location in crystalline germanium is analyzed. An increase in the annealing temperature is shown to lead to the antimony atoms going out of lattice.

Several experimental studies are conducted to explain the optical properties, as well as the impact of [Er.sup.3+] concentration on the luminescence in the [Y.2?x][Er.x][O.sub.3] thin films on Si. The high concentration regions are shown to lead to an increase in the nonradiative decay rate of the compounds.

The structural and optical properties of Si-rich silicon oxide (SRSO) layers obtained by plasma enhanced chemical vapor deposition (PECVD) and magnetron sputtering is examined. The studies have shown that in PECVD films only around 30% of the Si excess agglomerates in clusters while an almost complete agglomeration has occurred in sputtered films.

Different experimental techniques are used for determining the lattice deformation induced by substitutional B in Si. The results have led to more accurate strain determination, which is in agreement with other ab initio theoretical calculations.

The formation of He ion implantation induced nanovoids in Si and its influence on the self-interstitial (Is) supersaturation, thus affecting the diffusion and electrical activation of implanted boron in crystalline silicon are described. The uniform nanovoid distribution has determined a peculiar B box like shape and the simulation of B diffusion has indicated that changes in the B profile are attributed to a local suppression of the interstitial supersaturation (S) caused by the presence of the nanovoids.

The results of experiments aimed at a more comprehensive understanding of the [Fe.sup.2+/3+] center activation process are presented. The overall results show that the electrical behavior and the [Fe.sup.2+] deep trap activation properties are strictly related to the annealing evolution of the implant-induced damage and to the escape process of the Fe atoms from substitutional sites that in turn is controlled by the background doping density in the substrated.

The structural and optical properties and the room temperature luminescence of Er2O3 thin films deposited by magnetron sputtering are analyzed. The enhanced efficiency of the photon emission process is correlated with the longer lifetime of the photoluminescence (PL) signal and the conditions leading to a reaction of Er2O3 with the substrate are identified.

Pump and probe transmission experiments were used to measure net optical gain in silicon nanocrystals (Si-nc). Plasma enhanced chemical vapor deposition produces Si-nc active layers on transparent quartz substrates.

An investigation of the energy transfer mechanism in an aluminosilicate glass coimplanted with Si and Er, in relation to the structural properties of the material is presented. A postimplantation annealing is performed at different temperatures in order to recover the damage left over by the implantation process, to promote Si nucleation, and to maximixe the photoluminescence (PL) emission at 1.54 (mu) m.

The real and imaginary parts of third-order nonlinear susceptibility Chi(super (3)) is measured for silicon nanocrystals embedded in SiO2 matrix, formed by high temperature annealing of SiO(sub x) films prepared by plasma-enhanced chemical vapor deposition. The absolute value of Chi(super (3)) is on the order of 10(super -9) esu and reflects an increase as the silicon nanocrystalline size decreases.

We have studied the electrical activation of the Fe2+/3+ trap in Fe-implanted InP by means of capacitance-voltage and deep level transient spectroscopy analyses. Five deep traps have been identified and we have characterized the concentration and depth distribution of the Fe2+/3+ deep trap, located at EC–0.66 eV. The InP substrate background doping, i.e., the Fermi-level position, plays a crucial role in the Fe activation process by setting an upper limit to the amount of Fe centers electrically activated as deep acceptor traps. [ABSTRACT FROM AUTHOR]

Accurate first-principles calculations of soft x-ray absorption spectra are compared with experimental data obtained for the ion-implanted MnxGe1-x ferromagnetic semiconductor. The well-defined features in the spectra are recognized as a signature of homogeneous Mn dilution within the Ge host, as demonstrated by comparing the Mn spectra in diluted MnGe alloys with other competing Mn–Ge crystalline phases. Moreover, provided that an efficient Mn dilution is achieved, the nature of the semiconducting host is shown to affect only slightly the Mn absorption spectrum, as shown by the similarity of the present results with those for other magnetic semiconductors. Both these findings establish the relevance of ion-implantation in the dilute magnetic semiconductor framework, emphasizing its potential impact in device technology. [ABSTRACT FROM AUTHOR]

Abstract: Ge (100) wafers were implanted with 100keV Mn+ ions with a dose of 2×1016 ions/cm2 at different temperatures, ranging from 300 to 573K. The surface morphology of implanted samples, analyzed with scanning electron microscopy and atomic force microscopy measurements, reveals for the 300–463K implant temperature range the formation of a surface swelled and porous film, containing sponge-like structures. On the contrary, samples implanted in the 513–573K temperature range present an atomically flat surface, with a roughness less than 1nm, indicating that crystalline order has been preserved. X-ray photoemission spectroscopy depth profiling measurements indicate the presence of adsorbed oxygen in the porous layer of lower-temperature implanted samples, as well the presence of a large Mn concentration below the expected end of range for impinging ions. Mn and O concentrations at anomalously great depths are maximum in the 413K implanted sample, indicating that the phenomenon of ion beam induced porosity is best favored at a well defined temperature. [Copyright &y& Elsevier]