Victor Strelchuk

Comparative investigation of structural and optical properties of Si-rich oxide films fabricated by magnetron sputtering

RF magnetron sputtering of two separate silicon and oxide (SiO2 or Al2O3) targets in pure argon plasma was used for deposition of Six(SiO2)1-x and Six(Al2O3)1-x films with x=0.15-0.7 on long fused quarts substrate. The effect of post-fabrication treatments on structural and light emitting properties of the films with different x values was investigated by means of Raman scattering, electron paramagnetic resonance and X-ray diffraction as well as by photoluminescence (PL) methods. The formation of amorphous Si clusters upon deposition process was found for the both types of films. The annealing treatment at 1150°C during 30 min results in formation of Si nanocrystallites (Si-ncs). The latter were found to be larger in Six(Al2O3)1-x films than that in Six(SiO2)1-x counterparts with the same x values and are under tensile stresses. The investigation of photoluminescence properties of annealed films of both types revealed the appearance of visible-near infrared light emission. The Six(SiO2)1-x films demonstrated one broad PL band which peak position shifts gradually to from 1.4 eV to 1.8 eV with the x decrease. Contrary to this, for the Six(Al2O3)1-x films two overlapped PL bands were observed in the 1.4-2.4 eV spectral range with peak positions at ~2.1 eV and ~1.7 eV accompanied by near-infrared tail. Comparative analysis of PL spectra of both types samples showed that the main contribution to PL spectra of Six(SiO2)1-x films is given by exciton recombination in the Si-ncs whereas PL emission of Six(Al2O3)1-x films is caused mainly by carrier recombination either via defects in matrix or via electron states at the Si-ncs/matrix interface.

Photoluminescence and Raman Scattering Behavior of Si Rich Silicon Oxynitride Films Annealed at Different Temperatures

In this work, we study the photoluminescence and the Raman scattering behavior of Si rich silicon oxynitride films obtained by plasma enhanced chemical vapor deposition as a result of thermal anneals during 1 hour in the temperature range from 400O to 1100OC and discuss the ways of the transformation of structure in them.

Photoluminescence Spectroscopy of Neutron-Irradiated Cubic SiC Crystals

Photoluminescence (PL) spectroscopy has been used to characterize neutron-irradiated cubic silicon carbide crystals. The effects of thermal annealing (600-1100OC) on the PL bands have been studied. Several PL bands consisting of a sharp line and its phonon replicas have been observed in the 9-80 K temperature range. Certain of them like the D1 spectrum doublet with 1.975 eV and 1.977 eV zero-phonon lines (ZPL) at 9 K and the L2 spectrum with ZPL at 1.121 eV were reported previously for ion-implanted and electron irradiated 3C-SiC crystals, respectively. Besides, some new bands with ZPL at 2.027, 1.594, 0.989 and 0.844 eV and a broad band at 1.360 eV have been found. A correlation of PL and EPR spectra intensities of these neutron-irradiated and annealed cubic SiC crystals is briefly discussed.

An Experimental Study of Properties of Ultrathin Si Layer with Bonded Si/SiO2 Interface

Properties of Si/buried oxide (BOX) systems with bonded interface in silicon-on-insulator (SOI) wafers were studied in this paper. Results show impact of the starting Si material - Czochralski (Cz) or float-zone (Fz) grown silicon on the electron mobility (μe) and BOX charge behavior in ultrathin SOI layers. In particular, there were found: 1) the μe ~ Ne-0.3 dependencies at the electron density Ne in the range of 4х (1011-1012) cm-2 in accumulation Cz-SOI layers with the μe degradation when Si thickness decreases from 20 to 9 nm, and 2) the ~ Ne-0.6 behavior of mobility with no degradation in Fz-SOI layers. Raman spectroscopy shows the structural modification of Cz-SOI layers. An origin of degradation of the electrical and structural properties for ultrathin SOI layer is discussed.