Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

The material properties of two ultra low-k organic polymers are characterized for copper interconnect integration. The k-values are 2.2-2.3 for both. Compared to OSG materials of similar k-values, these polymers have lower porosity and smaller pore size, achieved using selfassembled chemistry. Both materials demonstrate excellent resistance to plasma damage: no water uptake was detected after exposure to selected etching plasmas. This characteristic, combined with the small pore size and low porosity, results in the successful integration of the organic low-ks in 80 nm spacing with no significant increase in the integrated k-values.

It is found that higher open porosity in polymer A is accompanied by higher leakage current, which is not however linked to lower dielectric breakdown lifetimes.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Effect of timing of pregnant mares's serum gonadotrophin (PMSG) injection combined with a progestagen-impregnated vaginal sponge on fixed-time artificial insemination with fresh, undiluted semen during the nonbreeding season was investigated. PMSG injection 2 days before sponge removal (group A) caused significantly earlier oestrus than injection at the time of sponge removal (group B). Lambing percentages in a total of 320 ewes after fixed-time insemination at 36 h (64·1%) and 48 h (47·2%) in group A, and 48 h (59·5%) and 60 h (39·5%) in group B were not significantly different from those resulting from ‘at oestrus’ insemination (500% and 511% in groups A and B, respectively). The present results indicate that the optimum time for fixed insemination may depend upon the time of PMSG injection associated with progestagen treatment.

We report high-mobility rubrene single-crystal field-effect transistors with ionic-liquid electrolytes used for gate dielectric layers. As the result of fast ionic diffusion to form electric double layers, their capacitances remain more than 10 μF/cm2 even at 0.1 MHz. With high carrier mobility of 1.2 cm2/Vs in the rubrene crystal, pronounced current amplification is achieved at the gate voltage of only 0.2 V, which is two orders of magnitude smaller than that necessary for organic thin-film transistors with dielectric gate insulators. The results demonstrate that the ionic-liquid/organic semiconductor interfaces are suited to realize low-power and fast-switching field-effect transistors without sacrificing carrier mobility in forming the solid/liquid interfaces.

Gating organic transistors with electric double layers (EDL) of electrolytes is advantageous in injecting high-density carriers with the application of minimum gate voltage. The drawback of such devices, however, has been that commonly used polymer electrolytes suffer relatively slow ionic diffusion before forming the EDLs. In this report, we disclose a new class of EDL devices incorporating low-viscosity room temperature ionic liquid as the electrolyte layer, so that the rapid ionic diffusion allows MHz operation for the transistor performance. We fabricate a well structure using an elastomeric rubber stamp of poly-dimethylsiloxane to hold the ionic liquid 1-ethyl 3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide, known for high ionic conductivity. The transistor performs without hysteresis with the carrier mobility of 5 cm2V−1s−1, realizing the highest sheet transconductance ever achieved.

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

A low temperature method for uniform growth of In2O3 nanostructures on Si wafers that does not require separate catalyst materials or template-assistance is investigated. Nanostructures are uniformly deposited on either bare or SiO2 thin film coated Si substrates via DC magnetron sputtering at 200-400°C using a 90% In2O3 / 10% SnO2 (ITO) target. The nanostructures are approximately 500 nm long, sit atop an accompanying underlying 100 nm conductive film, and are conically shaped, with a diameter of about 80 nm at the base, tapering to a point that is capped with a spherical “ball”. X-ray diffraction (XRD) indicates a cubic In2O3 phase. Field emission from the tips is observed at a base pressure of 10-8 Torr with turn-on fields in a range between 45-75 V/cm and threshold fields from 64-105 V/cm. Nanocone growth is investigated with respect to O2 and Ar flow rates, temperature, power, pressure, wafer rotation, and time.

Background. Schneider's first-rank symptoms involve an alienated feature of the sense of one's own mental or physical activity. To clarify the brain morphological basis for the production of these symptoms, volumes of the frontal and medial temporal regions and their clinical correlates were examined in patients with schizophrenia.

Method. Twenty-two patients with schizophrenia and 44 age- and gender-matched healthy control subjects were included. All patients were in their psychotic episodes with definite Schneiderian symptoms, rated by using the Scale for Assessment of Positive Symptoms. Volumetric measurements of high-resolution magnetic resonance imaging were performed in the prefrontal area, cingulate gyrus, and precentral gyrus, and the medial temporal structures such as the amygdala, hippocampus, and parahippocampal gyrus.

Results. Patients had significantly decreased volumes in the cingulate gray matter and the amygdala compared to controls. In the patient group, Schneiderian symptom severity showed significant inverse correlations with volumes of the right posterior cingulate gray matter and of the left anterior parahippocampal gyrus.

Conclusions. Schneiderian symptoms may be associated with morphological abnormalities in the limbic-paralimbic regions such as the cingulate gyrus and parahippocampal gyrus, which possibly serve the self-monitoring function and the coherent storage and reactivation of information.

Thin films deposited via atomic layer deposition at low temperature tend to be less dense than bulk material and typically require high temperature post deposition annealing for densification and removal of unreacted precursor ligands. We have found that improved film densification can be achieved by interval annealing, in which in-situ moderate temperature (∼420°C) rapid thermal anneals are performed after every n deposition cycles. HfO2 film density and refractive index were found to increase with decreasing anneal interval (more frequent annealing). The highest density films could be achieved only by every-cycle annealing and could not be achieved by post deposition annealing. The densified every cycle annealed films have been shown to have improved equivalent thickness and leakage and decreased interfacial layer thickness.

Anomalous growth of silicon (Si) nanocrystals (NCs) was observed during Raman scattering measurements of nanosilica SiOx (x=0.9) powder with an average diameter of 40 nm. It was found that Si NCs were formed by exposure to the laser beam. This photo-assisted synthesis is similar to the thermal synthesis of Si NCs, which forms Si NCs by thermally decomposing SiOx into Si and SiO2. However, the photo-assisted synthesis is more effective in forming Si NCs than the thermal synthesis. Even one second after irradiation of the nanosilica SiOx powder with laser, Si NCs with an average size of 5 nm were formed. The Si NC size increases with increasing the laser power and exposure time. It is interesting to observe a self-limited size for higher laser power and prolonged exposure. The photo-assisted synthesis of Si NCs is proved to be a promising technique with a wide range of applications in nanotechnology.