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Programming with larger current than optimized one is often preferable to ensure a good resistance distribution of high-resistive reset state in high-density phase-change random access memories because it is very effective to increase the resistance of cells to a target value. In this paper, we firstly report that this larger current writing may conversely degrade the reset distribution by reducing the resistance of normal cells via the partial crystallization of amorphous Ge2Sb2Te5 and this degradation can be suppressed by designing a novel cell structure with a heat dissipating layer.

Fully functional 512Mb PRAM with 0.047mum2 (5.8F2) cell size was successfully fabricated using 90nm diode technology in which the authors developed novel process schemes such as vertical diode as cell switch, self-aligned bottom electrode contact scheme, and line-type Ge2Sb2Te5. The 512Mb PRAM showed excellent electrical properties of sufficiently large on-current and stable phase transition behavior. The reliability of the 512Mb chip was also evaluated as a write-endurance over 1E5 cycles and a data retention time over 10 years at 85degC

A wide-band SBS slow light method is achieved by phase-modulating the Brillouin pump. A 1-Gb/s RZ PRBS data is delayed by 600ps with certain pulse distortion using such a technique.

Advanced ring type technology and encapsulating scheme were developed to fabricate highly manufacturable and reliable 256Mb PRAM. Very uniform BEC area was prepared by the advanced ring type technology in which core dielectrics were optimized for cell contact CMP process. In addition, relatively high set resistance was stabilized from encapsulating Ge2Sb2Te5 (GST) stack with blocking layers, thus giving rise to a wide sensing window. These advanced ring type and encapsulating technologies can provide great potentials of developing high density 512Mb PRAM and beyond

Advanced bottom electrode contact (BEC) scheme was successfully developed for fabricating reliable high density 64 Mb PRAM by using ring type contact scheme. This advanced ring type BEC scheme was prepared by depositing very thin TiN films inside a contact hole, and then core dielectrics was uniformly filled into the TiN-deposited contact hole. Using this novel contact scheme, it was possible to reduce a reset current with low set resistance, and also maintain a uniform cell distribution. Thus, it is clearly demonstrated that the ring type BEC technology can exhibit strong feasibility of high density 256 Mb PRAM and beyond.

Novel small contact fabrication technologies were proposed to realize reliable high density 256Mb PRAM(phase change memory) product. Introducing the 2-step CMP (chemical mechanical polishing) process and the ring-shaped contact structure, the contact area distribution was greatly improved even at the smallest contact diameter of 50nm node. The validity of this approach was directly confirmed by the evaluation of the functionality for the fabricated 256Mbit PRAM based on 0.10/spl mu/m CMOS technology.

In this paper, we propose a text extraction method from camera-captured document style images and propose a text segmentation method based on a color clustering method. The proposed extraction method detects text regions from the images using two low-level image features and verifies the regions through a high-level text stroke feature. The two level features are combined hierarchically. The low-level features are intensity variation and color variance. And, we use text strokes as a high-level feature using multi-resolution wavelet transforms on local image areas. The stroke feature vector is an input to a SVM (support vector machine) for verification, when needed. The proposed text segmentation method uses color clustering to the extracted text regions. We improved K-means clustering method and it selects K and initial seed values automatically. We tested the proposed methods with various document style images captured by three different cameras. We confirmed that the extraction rates are good enough to be used in real-life applications.

A 64 Mb phase change random access memory, based on 0.18 /spl mu/m technology is developed. We proposed several key factors such as BEC and GST cell size, contributing to stabilization of writing current for reversible cell transition. By reducing writing current to 1.1 mA through such optimization, we have developed a 64 Mb PRAM. With memory functions and reliability tests, the feasibility for developing high-density 64 Mb PRAM is presented.

The optimization of amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction solar cells was performed in terms of emitter material and heterointerface. Various conditions were explored and monitored by a residual gas analyzer. In addition, a thin microcrystalline (/spl mu/c-Si) buffer layer was inserted into the heterojunction to improve the interface by bandgap grading. The conduction behavior is strongly influenced by the defect distribution and band offset at the hetero-interface. The recombination process dominates at low forward bias (V 0.55 V). The reduced band offset at the interface increases current levels by the enhanced diffusion/emission process. The solar cell with a 700 /spl Aring/ a-Si:H top layer and a 200 /spl Aring/, /spl mu/c-Si buffer layer shows the maximum solar cell efficiency of around 10 %, without an antireflective coating by improving both the carrier transport and the red response of the cell.

In this paper four typical watermarking techniques are compared and tested extensively, which not only include the private system, the semi-private system but also the public schemes. The comparisons mainly focus on the evaluation of robustness and visual image quality. The benchmarking is the popular Stirmark 3.1. Results show that the chosen schemes do not have the same behavior and no method has all the desirable characteristics.

A compact array of multiwavelength vertical-cavity surface-emitting laser (VCSEL) directly-coupled to single multimode fiber can be a promising solution for high data transmission rates. Several techniques have been introduced to fabricate multiwavelength VCSELs. Among them postgrowth wavelength adjustment methods are considered to be more desirable than the growth methods due to relatively good controllability and simplicity. In this reports we present a method to adjust wavelengths by varying the optical thickness of dielectric mirror precisely, which is feasible for fabricating multiwavelength VCSELs.