Highly reliable oxide‐semiconductor TFT for AMOLED displays

Abstract— The stability and reliability of oxide‐semiconductor TFTs were investigated. The contact material to the oxide semiconductor affected the thermal stability of the TFT, and a molybdenum‐contact source/drain showed good stability. And the passivating film and TFT structure affected the stability against bias stress and humidity stress, and dc‐sputtered Al²O³ passivation and fully covered channel structure with an etching stopper or source/drain showed good reliability. Moreover, high photo‐stability was confirmed by the bias‐enhanced photo‐irradiation stress test. An 11.7‐in.‐diagonal qHD AMOLED display was demonstrated to provide an applicable solution for a large‐sized OLED and an ultra‐high‐definition LCD‐TV mass production.     

The effect of post-treatments on the powder morphology of titanium dioxide (TiO2) powders synthesized for cold spray

In this study, a novel synthesis method of TiO₂ powders that can be cold sprayed is presented. The synthesis technique is a simple hydrolysis method of titanyl sulfate (TiOSO₄) in distilled water with a small addition of inorganic salt. At a relatively low hydrolysis temperature, pure anatase TiO₂ can be obtained and post-synthesis treatments (annealing or hydrothermal treatment) do not alter this phase structure. The powder is agglomerated with fine nano primary particles, with different post-synthesis treatments leading to different TiO₂ nanostructures. Annealing causes a significant growth of primary particles with the existence of internal pores within a particle. On the other hand, hydrothermal treatment produces a unique oriented agglomeration structure where the primary particles are agglomerated in one single crystal axes. It is believed that the synergistic effect of inorganic ion adsorption and post-treatments results in the observed nanostructures. After cold spraying, it is revealed that these TiO₂ powders could be deposited via supersonic solid phase deposition (cold spray).     

A 16-Mb Toggle MRAM With Burst Modes

This paper describes a recently developed 16-Mb toggle magnetic random access memory (MRAM). It has 100-MHz burst modes that are compatible with a pseudo-SRAM even though the toggle cell requires reading and comparing sequences in write modes. To accelerate operating clock frequency, we propose a distributed-driver wide-swing current-mirror scheme, an interleaved and pipelined memory-array group activation scheme, and a noise-insulation switch scheme. These circuit schemes compensate the toggle cell timing overhead in write modes and maintain write-current precision that is essential for the wide operational margin of MRAMs. Because toggle cells are very resistant to write disturbance errors, we designed the 16-Mb MRAM to include a toggle MRAM cell. The MRAM was fabricated with 0.13-mum CMOS and 0.24-mum MRAM processes with five metal layers.     

Improvement in Oxidation Resistance of Stainless Steel by Molten-Salt Electrodeposition of La

Improvement in the oxidation resistance of SUS304 stainless steel was accomplished by electrodeposition of La in a molten salt. The electrolysis of La was conducted using a potentiostatic-polarization method in an equimolar NaCl–KCl melt containing 3.5 mol. LaF ₃ at 1023 K. Observation of the specimen surface after polarization at –1.8 V (vs. Ag/Ag⁺ (0.1)) for 0.18 ks showed that La particles were uniformly dispersed on the surface. The oxidation resistance of the electrodeposited stainless steel was significantly improved as compared with the untreated stainless steel. The scale formed on the untreated stainless steel after oxidation was thick and consisted of Fe₂O₃ and Fe₃O₄, whereas the scale formed on the elecrodeposited stainless steel was extremely thin, and mainly consisted of Cr₂O₃.     

Monoclonal antibodies against pig ovarian follicular granulosa cells induce apoptotic cell death in cultured granulosa cells

Two monoclonal antibodies capable of inducing granulosa cell apoptosis were produced against granulosa cells prepared from antral follicles of pig ovaries. The healthy follicles, 4-5 mm in diameter, were dissected from the ovaries of gilts, and then granulosa cells were isolated. BALB/c female mice were immunized with the isolated granulosa cells. Antibodies against the granulosa cells were detected by immunofluorescent staining using frozen ovarian sections. The isolated spleen cells prepared from immunized mice producing antibodies against the granulosa cells were fused with Sp2/O-Ag 14 mouse myeloma cells by standard hybridization techniques. Two hybridoma clones, PFG-1 and PFG-2, which produced specific IgM antibodies against granulosa cells were selected. Western blotting analysis revealed that PFG-1 and PFG-2 antibodies specifically recognized cell-membrane proteins with molecular weights of 55 and 70 kD and isoelectric points of 5.9 and 5.4, respectively. The monoclonal antibodies immunohistochemically reacted with granulosa cells of healthy follicles. When the isolated granulosa cells prepared from healthy follicles were cultured in medium containing 0.1 or 10 micrograms/m/PFG-1 or PFG-2 antibodies, respectively, the cells underwent apoptosis as determined by nuclear morphology, DNA electrophoresis and flow cytometric analysis. In conclusion, these two monoclonal antibodies against granulosa cells have cell-killing activity in cultured granulosa cells.     

Direct observation of local strain field for ULSI devices

The in-depth profile of strain distribution from the silicon surface is one of the most important pieces of information for optimizing the device performance. The convergent-beam electron diffraction(CBED) method has been applied to analyze the local strain filed of the active regions for both test structure with the shallow trench isolation(STI) and the conventional LOCOS on a cross-sectional surface. As a result, strain distribution was observed successfully. It was found that the compressive stress exist all over the survey regions. The active region close to the bottom corner of the STI shows a larger stress than that of the conventional LOCOS. It is demonstrated that the CBED technique is very effective for the determination oflocal strain field in a small area of semiconductors and the optimizing of the STI structure andfabrication process.     

Joining of ADC12 and SS400 by means of friction stir welding

For conserving the earth's environment through the reduction of energy consumption in the field of transport machinery, reduction in weight is necessary and hence the application of light materials to structural members has been investigated. For the most representative example of transport machinery, it is highly likely that a variety of aluminium materials will be used for automobile bodies. However, since iron and steel materials are still used for the main part of the structure that requires high strength, joining of dissimilar metals, i.e. aluminium and iron and steel materials, is the new technical task in terms of reducing weight.     

Microstructure of Interfacial Region Between Cold-Sprayed Copper Coating and AlN Substrate Coated with Sputtered Titanium and Copper

Cold spraying has been developed as a high-quality coating technique. In this article, copper is deposited on an AlN substrate coated by the sputtering of titanium and copper at a low pressure of less than 1.0 MPa, making this approach suitable for a wide range of engineering applications. In order to understand the adhesion mechanism at the atomic scale, the interfacial regions are carefully observed in thin foil samples from the cross sections of the specimens with a HREM. We find a unique wavy boundary between the sputtered titanium and the sputtered copper. It is assumed that the shear-instability phenomenon occurs due to the cold-spraying process and influences the adhesive strength. Furthermore, the cold-sprayed copper particles are connected directly without any oxidation layer due to the appearance of new metallic surfaces during the impact process. The TEM data clearly reveal the phenomena and mechanisms related to the impact of powder sprayed on the substrate.