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The profound understanding of the mechanisms that affect the thermomechanical response of liquid-crystalline elastomers is of significant importance for applications. In the vicinity of a phase transition this response is reflected to the thermodynamic critical behavior. We demonstrate that two main-chain liquid-crystalline elastomers of identical composition, crosslinked in temperatures corresponding to different thermodynamic phases, exhibit dramatically different thermal behavior as derived from high-resolution calorimetry. Hence, a previously unexplored parameter for controlling the elastomers critical behavior is revealed, exhibiting a very strong effect. Moreover, the relative strength of various discovered mechanisms that control the critical behavior is discussed. [ABSTRACT FROM AUTHOR]

Polycrystalline silicon films deposited on oxidized wafer surfaces were implanted with As and annealed on a Varian IA-200 rapid thermal annealer. The effects of annealing conditions on resultant grain size of original as-deposited columnar grains are presented with a modified model for interfacially driven grain growth. During an initial temperature rise to 910 °C the original grain size (39 nm) and dopant profile are not significantly altered. At 1145 °C the grains have grown to 90 nm and the As is uniformly distributed throughout the film. Additional annealing to 1300 °C in 20 s causes grains to grow to 260 nm. Further grain growth is retarded due to the 300-nm film thickness. During annealing of unencapsulated films a substantial loss of As results in a lower rate of grain growth. When grain size increases, Hall mobility increases and resistivity decreases. [ABSTRACT FROM AUTHOR]

The structure of silicon carbide precipitates in oxygen-implanted and annealed silicon-on-insulator material was directly studied by high-resolution transmission electron microscopy. Epitaxially aligned precipitates 5–25 nm in size were located in the matrix silicon above and below the buried oxide layer with a density of 1×1010 cm-3. Precipitate-matrix interface strain was minimized by twinning and stacking fault formation in the precipitate and by amorphous silicon dioxide at the interface. The wide range of depths of the precipitates suggests that they are formed from trace amounts of carbon that are accelerated along with oxygen after mass analysis. [ABSTRACT FROM AUTHOR]

Polycrystalline Si films on oxidized Si wafers have been subjected to a rapid thermal processing anneal prior to As ion implantation. After ion implantation the films are given another rapid thermal processing anneal to activate the As. The preimplant anneal causes the as-deposited grain size to increase by ∼ a factor of 10. These films have a 20–30% lower sheet resistance than films that were post-implant annealed only. The increase in grain size by the preimplant anneal reduces the grain boundary area and therefore, minimizes the amount of dopant in the grain boundary relative to the grain. [ABSTRACT FROM AUTHOR]