Abstract: In present work the investigation of the electrochemical and chemical hydrothermal deposition processes of ZnO on silicon is presented. The influence of the electrochemical process parameters on the characteristics and morphology of the ZnO deposits is analyzed. Electrochemical deposition from non aqueous DMSO solutions on porous silicon buffer layer is also discussed. The details of the chemical hydrothermal deposition from the nitrate bath of high-quality ZnO crystals on silicon substrate are presented. It was shown that morphology and size of synthesized ZnO crystals depends on the temperature of the deposition bath. Differences between photoluminescence of electrochemically deposited ZnO thin films and hydrothermally synthesized crystals are shown. Electrochemically deposited ZnO films demonstrate defect-caused luminescence and hydrothermally grown ZnO crystals shows intensive exciton luminescence band in UV region. Hydrothermal deposition of high-quality ZnO crystals on the surface of electrochemically deposited ZnO seed layer with porous silicon buffer improves photoluminescence properties of the structure which is useful for optoelectronics applications. Possible applications of ZnO as gas sensors and photovoltaic devices are considered. Aspects of ZnO electrochemical deposition on bulk silicon and silicon-on-isolator wafers for integration purposes are discussed.
Abstract: This paper presents an analysis of the electrical characteristics of the amorphous silicon carbide films deposited on the SiO2/Si substrate. Aspects of RF plasma treatment on electrical and structural characteristics of a-SiC film are discussed. It is demonstrated that the dominant mechanism of current transport in the a-SiC thin film is determined by variable-range hopping conductivity at the Fermi level. Studies of the a-SiC film at temperatures from 300 K to 600 K also indicate that silicon carbide is a perspective material for fabrication of temperature sensor.
Abstract: Graphitic-diamond heterostructure may be very helpful not only for high frequency or power devices but also for new generation of electronic devices like single electron transistors or quantum computers operated at room temperature. The goal of our work was a formation of nanothin amorphous carbon or graphite layers with sp3 or sp2 hybridization inside the nitrogen doped synthetic monocristalline diamond by high dose hydrogen implantation. It was found that there is a “critical” dose of 50 keV hydrogen molecular ions equal to 4x1016 cm-2 above which an irreversible drop of the sheet resistivity in implanted layer occurs after annealing above 1000 oC. The nature of this conductivity was investigated and it was shown that variable range hopping mechanism of 3D conductivity dominates in investigated temperature interval. Four times higher value for the onset of this conductivity in comparison with “critical” dose for graphitization is explained by interaction of implantation induced defects with nitrogen atoms and surface defects.
Abstract: Hydrogen gettering by implantation-disturbed buried layers in oxygen-implanted silicon (Si:O, prepared by O2+ implantation at energy 200 keV and doses 1014 cm-2 and 1017 cm-2) was investigated after annealing of Si:O at up to 1570 K, also under enhanced hydrostatic pressure, up to 1.2 GPa. Depending on processing conditions, buried layers containing SiO2-x clusters and/or precipitates were formed. To produce Si:O,H, Si:O samples were subsequently treated in RF hydrogen plasma. As determined by Secondary Ion Mass Spectrometry, hydrogen was accumulated at the sample surface and within implantation-disturbed areas. It was still present in Si:O,H (D=1017 cm–2) even after subsequent annealing at up to 873 K. Hydrogen accumulation within disturbed areas of Si:O as well as of SOI can be used for recognition of defects in such structures.
Abstract: Theoretical model of thin film SOI MISFET based on the gate control of impact ionization avalanche in the drain induced p-n+ junction is developed. Such operation principle opens a way of the creation of transistors with high transconductance and operation frequency, and switching between the ON and OFF states by low gate voltage variation.
Abstract: A semi-analytical model which is applicable to description of ballistic field-effect transistors with low-dimensional channels is proposed. For instance, such transistors can be manufactured on a “silicon-on-insulator” wafer. The model accounts for single-gate and double-gate structures with one-dimensional and two-dimensional channels. It differently describes the regimes of a transistor above threshold and below threshold. The first implies an essential influence of charge inside the channel on a potential distribution; the second supposes a negligible charge inside the channel. Both approaches are mainly based upon an approximate solution of the Poisson equation.
Abstract: Mobility degradation during gate length scaling is a well established experimental fact, which is confirmed also by Monte –Carlo simulation. We have analyzed the physical reason for this degradation using experimental and modeling data obtained in classic drift-diffusional approximation with electric field dependences of electron mobility. We have shown that this dependence is a main reason for mobility degradation in nanoscale FETs, which means also that the same reason will limit the drain current in future post-silicon CMOS generation with new materials like narrow band III/V compounds or graphene with the highest carrier velocity near 108 cm/s.
Abstract: The effect of elevated temperature on the harmonic distortion in Graded-Channel MOSFETs is presented in this work. The Graded-Channel devices show interesting advantages in terms of nonlinear behavior compared to classical devices especially at higher temperatures up to 200°C.
Abstract: The paper discusses some issues of modeling the MOS tunnel structure with a gate stack containing a semiconductor quantum well (double barrier MOS system). The considerations are illustrated by simulations with the use of a theoretical model. Results of simulations are compared with experimental characteristics of fabricated DB MOS diodes.