Directed self-assembly (DSA) of lamellar phase block-co-polymers (BCPs) can be used to form nanoscale line-space patterns. However, exploiting the potential of this process for circuit relevant patterning continues to be a major challenge. In this work, we propose a way to impart two-dimensional pattern information in graphoepitaxy-based lamellar phase DSA processes by utilizing the interactions of the BCP with the template pattern. The image formation mechanism is explained through the use of Monte Carlo simulations. Circuit patterns consisting of the active region of Si FinFET transistors, referred to as Si "fins", were fabricated to demonstrate the applicability of this technique to the formation of complex patterns. The quality of the Si fin features produced by this process was validated by demonstrating the first functional DSA-patterned FinFET devices with 29 nm-pitch fins.

Among the challenges hindering the integration of carbon nanotube (CNT) transistors in digital technology are the lack of a scalable self-aligned gate and complementary n- and p-type devices. We report CNT transistors with self-aligned gates scaled down to 20 nm in the ideal gate-all-around geometry. Uniformity of the gate wrapping the nanotube channels is confirmed, and the process is shown not to damage the CNTs. Further, both n- and p-type transistors were realized by using the appropriate gate dielectric-HfO2 yielded n-type and Al2O3 yielded p-type-with quantum simulations used to explore the impact of important device parameters on performance. These discoveries not only provide a promising platform for further research into gate-all-around CNT devices but also demonstrate that scalable digital switches with realistic technological potential can be achieved with carbon nanotubes.

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Pentacene thin film transistors ͑TFTs͒ were fabricated by the organic molecular beam deposition method. The TFTs were characterized in order to study the effect of thermal annealing on the morphology and carrier mobility of the transistors. For all the TFT samples the mobility exhibited an Arrhenius relationship with temperature, indicating a thermally activated transport that could be explained by the carrier trap and thermal release transport mechanism. Therefore, in order to investigate the annealing effect, we tested the data for a significant period of time after annealing until the temperature recovered to room temperature, so that the thermal activation effect was screened and possible effects of thermal expansion and stress were also ruled out. As a result, we found that only with a temperature below a critical temperature of approximately 45°C could annealing improve the mobility, while annealing with T Ͼ 50°C would decrease the mobility compared to the value before annealing. Atomic force microscopy observation and x-ray diffraction ͑XRD͒ data indicated that annealing caused decreased grain size and decreased XRD peak intensity for all samples. Increasing the annealing temperature to 70°C caused obvious desorption because of the low van der Waals intermolecular forces in the organic film. The mobility deterioration after high temperature annealing may be ascribed to the deteriorated microstructure, while the improved mobility may result from the increased crystallinity in the bottom several layers near the substrate film interface. The results also suggested that the influence of possible structure evolution should be distinguished when investigating temperature dependent transport properties.

Articles you may be interested inPolymethyl methacrylate/hydrogen silsesquioxane bilayer resist electron beam lithography process for etching 25 nm wide magnetic wires J. Vac. Sci. Technol. B 32, 021601 (2014); 10.1116/1.4867753 Modular ultrahigh vacuum-compatible gas-injection system with an adjustable gas flow for focused particle beam-induced deposition Electrodes for carbon nanotube devices by focused electron beam induced deposition of gold Local coinjection of a ͑H 2 -Ar͒ microplasma jet and Cu͑O 2 C 5 F 6 H͒ 2 molecules during focused electron beam-induced deposition ͑FEBID͒ was studied with respect to changes in the Cu:C ratio of deposits. Microplasma-assisted FEBID ͑30 keV and 1 nA͒ decreased codeposition of carbon, oxygen, and fluorine originating from the chamber background and the precursor molecule. The copper metal content could be increased to 41 at. %, being almost four times more than in conventional FEBID deposits without coinjection. Conventional FEB deposits from Cu͑O 2 C 5 F 6 H͒ 2 resulted in 11-12 at. % Cu content. Microplasma post-treatments of conventional FEB deposits resulted in volume changes, surface roughening, and an increase of the overall Cu content to 27 at. %. The removal mechanisms were of nonthermal nature. At repulsive bias potentials from 0 to +30 V, a pure chemical etching of the carbonaceous matrix by atomic hydrogen radials occurred. At attractive bias potentials of up to Ϫ30 V, a more efficient ion induced chemical sputtering regime prevailed where Ar + ions break carbon bonds, which in turn will be passivated by atomic hydrogen radicals to form volatile hydrocarbon compounds.