Abstract: Disclosed is a transmitting and receiving method for reducing a time-varying channel distortion in an orthogonal frequency division multiplex (OFDM) system. In the present invention, the transmitter defines M sub-channels in one data group, mathematically analyzes a change of channel for each path causing a time-varying channel distortion in a high-speed mobile environment by approximation, calculates a weight value based on the mathematical analysis and assigns the calculated weight value to transmit data of each sub-channel. Subsequently, the receiver combines the signals of these M sub-channels and demodulates the combined signals. Accordingly, the present invention greatly reduces a distortion caused by the time-varying channel to improve a bit error rate and a channel estimation performance.

Abstract: A method of forming a semiconductor device includes a liner is conformally stacked on a semiconductor substrate before coating an SOG layer thereon, and then curing the SOG layer, preferably in an ambient of oxygen radicals formed at a temperature of 1000° C. or higher when oxygen and hydrogen are supplied. The oxygen radicals are preferably formed by irradiating ultraviolet rays to ozone or forming oxygen plasma. The SOG layer is preferably made of a polysilazane-based material that may promote a conversion of the SOG layer into a silicon oxide layer.

Abstract: A method of fabricating a semiconductor device using a trench isolation method including a hydrogen annealing step, wherein a photoresist pattern is formed on a semiconductor substrate, a pad insulating layer may be formed before forming the photoresist pattern, the semiconductor substrate is etched using the photoresist pattern as an etching mask to form a trench, and an isolation layer is formed in the trench. To remove damages created in an active region defined by the isolation layer, the semiconductor substrate having the isolation layer is annealed in a hydrogen atmosphere.

Abstract: A semiconductor device having a Y-shaped isolation layer and a method for manufacturing the same are provided. The semiconductor device includes a Y-shaped isolation layer, which comprises side walls characterized by first and second slopes on the sides of the isolation layer. The method for manufacturing the isolation layer includes the step of forming a trench in a semiconductor substrate using a photoresist pattern as an etching mask. Next, a thermal oxide film is formed on the surface of the semiconductor substrate, and then a thin nitride liner is formed on the thermal oxide film. The nitride liner prevents oxidation of the side wall of the trench and also acts as a planarization stop layer. Thereafter, a gap-filling isolation layer is formed to fill the trench such that the nitride liner is separated or thinner at the upper corners of the trench. Next, the gap-filling isolation layer is planarized using the nitride liner as a planarization stop layer.

Abstract: Provided is a Pt—Ru based quaternary metal anode catalyst for a direct methanol fuel cell (DMFC). The Pt—Ru based quaternary metal anode catalyst has high activity to methanol oxidation and strong resistance to catalyst poisoning due to carbon monoxide (CO), which is a byproduct of the methanol oxidation.

Abstract: A method of fabricating a semiconductor device using a trench isolation method including a hydrogen annealing step, wherein a photoresist pattern is formed on a semiconductor substrate, a pad insulating layer may be formed before forming the photoresist pattern, the semiconductor substrate is etched using the photoresist pattern as an etching mask to form a trench, and an isolation layer is formed in the trench. To remove damages created in an active region defined by the isolation layer, the semiconductor substrate having the isolation layer is annealed in a hydrogen atmosphere.

Abstract: Methods are provided for conductively contacting an integrated circuit, including a plurality of spaced apart lines thereon, using a dummy dielectric layer. A dummy dielectric layer is formed between first selected ones of the spaced apart lines. An interdielectric layer is formed between second selected ones of the spaced apart lines that are different from the first selected ones of the lines. The interdielectric layer has a lower etch rate than the dummy dielectric layer with respect to a predetermined etchant. The dummy dielectric layer is etched with the predetermined etchant, to remove at least some of the dummy dielectric layer between the first selected ones of the spaced apart lines. A conductive layer is formed between the first selected ones of the spaced apart lines from which at least some of the dummy dielectric layer has been removed, to electrically contact the integrated circuit between the first selected ones of the spaced apart lines.

Abstract: Trench isolation methods for integrated circuits may reduce irregularities in the formation of an isolation layer through use of a high selectivity chemical-mechanical polishing (CMP) operation. In particular, a substrate surface is etched to form a trench. An insulation layer is then formed on the substrate surface and in the trench. The insulation layer is chemical-mechanical polished using a slurry that includes a CeO2 group abrasive to form an isolation layer in the trench. The CMP selectivity ratio of a slurry that includes a CeO2 group abrasive may be sufficient to allow the substrate surface to be used as a CMP stop. As a result, a more consistent level of polishing may be maintained over the substrate surface, which may result in a more uniform thickness in the isolation layer.

Abstract: A method of fabricating a semiconductor device using a trench isolation method including a hydrogen annealing step, wherein a photoresist pattern is formed on a semiconductor substrate, a pad insulating layer may be formed before forming the photoresist pattern, the semiconductor substrate is etched using the photoresist pattern as an etching mask to form a trench, and an isolation layer is formed in the trench. To remove damages created in an active region defined by the isolation layer, the semiconductor substrate having the isolation layer is annealed in a hydrogen atmosphere.

Abstract: A method for preparing a platinum alloy electrode catalyst for DMFC using anhydrous metal chlorides. The method includes reducing platinum chloride and non-aqueous second metal chloride with boron lithium hydride (LiBH4) in a water-incompatible organic solvent in a nitrogen atmosphere to form nano-sized particles of colloidal platinum alloy, and drying the platinum alloy particles without any heat treatment. The method of preparing a platinum alloy catalyst according to the present invention makes it possible to prepare platinum alloy particles having a narrow range of size distribution and an average particle size of less than 2 nm with ease, relative to the conventional methods. The platinum alloy particles thus obtained can be used as an electrode catalyst for DMFC to enhance methanol oxidation performance.

Abstract: An isolation method for a semiconductor device where an insulating mask layer is formed on desired regions of a semiconductor substrate. A trench is formed to a desired depth in the semiconductor substrate using the insulating mask layer as a mask. An oxide layer is formed on the insulating mask layer and on the sidewall of the trench. A trench liner layer is formed on the oxide layer. An insulating filler layer is formed in the trench in the semiconductor substrate, on which the trench liner layer is formed, so as to fill the trench. The insulating mask layer is removed. According to the isolation method for a semiconductor device, it is possible to reduce dents from occurring along the edge of the trench, reduce a bird's beak type oxide layer from occurring at an interface between the insulating mask layers, decrease the leakage current, or improve the electrical characteristics, such as threshold voltage.

Abstract: A method of forming a semiconductor device includes a liner is conformally stacked on a semiconductor substrate before coating an SOG layer thereon, and then curing the SOG layer, preferably in an ambient of oxygen radicals formed at a temperature of 1000° C. or higher when oxygen and hydrogen are supplied. The oxygen radicals are preferably formed by irradiating ultraviolet rays to ozone or forming oxygen plasma. The SOG layer is preferably made of a polysilazane-based material that may promote a conversion of the SOG layer into a silicon oxide layer.

Abstract: A trench isolation structure which prevents a hump phenomenon and an inverse narrow width effect of transistors by rounding the top edges of a trench and increasing the amount of oxidation at the top edges of a trench, a semiconductor device having the trench isolation structure, and a trench isolation method are provided. In this trench isolation method, a trench is formed in non-active regions of a semiconductor substrate. An inner wall oxide film having a thickness of 10 to 150 Å is formed on the inner wall of the trench. A liner is formed on the surface of the inner wall oxide film. The trench is filled with a dielectric film. Part of the liner is etched so that the top ends of the silicon nitride liner are recessed from the surface of the semiconductor substrate.

Abstract: A frequency synchronization apparatus for an orthogonal frequency division multiplexing (OFDM) communication system includes a radio frequency (RF) receiving module for receiving OFDM signal, an analog/digital (A/D) converter connected to the RF receiving module, the A/D converter converting the OFDM signal into a digital signal, a frequency synchronization module connected to the A/D converter, the frequency synchronization module synchronizing carrier frequency, a Fast Fourier Transformer (FFT) connected to the frequency synchronization module, the FFT performing fast Fourier transformation to symbols from the frequency synchronization module, a channel estimation module connected to the FFT, the channel estimation module estimating channel response, an equalizer connected to the FFT and the channel estimation module, the equalizer equalizing channel, a residual phase tracking module connected to the equalizer, the residual phase tracking module tracking residual phase, a demodulator connected to the residu

Abstract: A method for forming a conductive contact of a semiconductor device is provided. According to one aspect of the present invention, a dummy dielectric layer pattern having a dummy opening and an interdielectric layer pattern having a lower etch-rate than that of the dummy dielectric layer, for filling the dummy opening are formed on a semiconductor substrate. The dummy dielectric layer pattern using the interdielectric layer pattern as an etching mask is selectively removed, and a contact opening for exposing the semiconductor substrate of a portion in which the dummy dielectric layer pattern is located.

Abstract: Methods are provided for conductively contacting an integrated circuit, including a plurality of spaced apart lines thereon, using a dummy dielectric layer. A dummy dielectric layer is formed between first selected ones of the spaced apart lines. An interdielectric layer is formed between second selected ones of the spaced apart lines that are different from the first selected ones of the lines. The interdielectric layer has a lower etch rate than the dummy dielectric layer with respect to a predetermined etchant. The dummy dielectric layer is etched with the predetermined etchant, to remove at least some of the dummy dielectric layer between the first selected ones of the spaced apart lines. A conductive layer is formed between the first selected ones of the spaced apart lines from which at least some of the dummy dielectric layer has been removed, to electrically contact the integrated circuit between the first selected ones of the spaced apart lines.

Abstract: A method for forming a conductive contact of a semiconductor device is provided. According to one aspect of the present invention, a dummy dielectric layer pattern having a dummy opening and an interdielectric layer pattern having a lower etch-rate than that of the dummy dielectric layer, for filling the dummy opening are formed on a semiconductor substrate. The dummy dielectric layer pattern using the interdielectric layer pattern as an etching mask is selectively removed, and a contact opening for exposing the semiconductor substrate of a portion in which the dummy dielectric layer pattern is located.

Abstract: A trench isolation structure which prevents a hump phenomenon and an inverse narrow width effect of transistors by rounding the top edges of a trench and increasing the amount of oxidation at the top edges of a trench, a semiconductor device having the trench isolation structure, and a trench isolation method are provided. In this trench isolation method, a trench is formed in non-active regions of a semiconductor substrate. An inner wall oxide film having a thickness of 10 to 150 Å is formed on the inner wall of the trench. A liner is formed on the surface of the inner wall oxide film. The trench is filled with a dielectric film. Part of the liner is etched so that the top ends of the silicon nitride liner are recessed from the surface of the semiconductor substrate.

Abstract: A trench isolation structure which prevents a hump phenomenon and an inverse narrow width effect of transistors by rounding the top edges of a trench and increasing the amount of oxidation at the top edges of a trench, a semiconductor device having the trench isolation structure, and a trench isolation method are provided. In this trench isolation method, a trench is formed in non-active regions of a semiconductor substrate. An inner wall oxide film having a thickness of 10 to 150Å is formed on the inner wall of the trench. A liner is formed on the surface of the inner wall oxide film. The trench is filled with a dielectric film. Part of the liner is etched so that the top ends of the silicon nitride liner are recessed from the surface of the semiconductor substrate.

Abstract: Disclosed is a method of preparing a platinum alloy electrode catalyst for DMFC using anhydrous metal chlorides, which method includes reducing platinum chloride and non-aqueous second metal chloride with boron lithium hydride (LiBH4) in a water-incompatible organic solvent in the nitrogen atmosphere to form a nano-sized particles of colloidal platinum alloy, and drying the platinum alloy particles without any heat treatment.