Observation of Geometry Induced Doping in Thin Si Nano-grating Layers

AbstractWe fabricate Si nano-grating layers and measure their electrical characteristics to monitor geometry induced doping. SOI device layer was thinned down by thermal oxidizing and subsequent wet etching of the oxide. Grating was fabricated using laser interference lithography (375nm laser) followed by reactive ion etching of Si. Next, large square island (0.5x0.5mm) was shaped in the device layer and four Si\Ti\Ag ohmic contacts were formed to measure electrical characteristics. The I-V characteristics were recorded using both 4 wire and 2 wire methods. Resistance-temperature dependences (T= 4-300K) were recorded as well. For all 12 samples, nano-grating layers show 2-3 order reduction of resistivity. Resistivity anisotropy was in the range 0.2-1 at 300K. Obtained geometry induced doping level corresponds to “effective impurity” concentration of 3x1018 cm-3. The dependence is in agreement with G-doping theory only below T=150K

Advanced Boron Carbide Matrix Nanocomposites Obtained from Liquid-Charge: Focused Review

Boron carbide is known as a hard material; it possesses a unique complex of physical-mechanical properties and has diverse applications in industries. An expansion of its field of uses stems from the creation of boron carbide matrix nanocomposite materials. In view of this perspective, an effective liquid-charge synthesizing method for their components in nanopowder form has been proposed. This paper provides a focused review on advanced boron carbide matrix ceramic and metal-ceramic nanocomposites recently obtained by the authors using this method. Particular attention is paid to the characterization of boron carbide nanocomposites, including some ceramic borides, metallic alloys and also other metal-ceramic composites