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The charge generation and transportation phenomena of OLED devices based on the different hole-transfer materials, HTL1 and HTL2, have been investigated employing Impedance Spectroscopy (IS) and Transient Electroluminescence (TEL). The capacitance resulted from the quantity of space charges in HTL1 and HTL2 have been observed to be distinguishable by means of both the Capacitance-Voltage and Frequency-dependent Capacitance measurements. The capacitance increment by the space charges is also seen in the extracted RC components of the equivalent circuit, which is determined from the comparison between the quantitatively calculated and the experimentally observed data in Cole-Cole plot. The increased space charges of HTL2 are found to enhance the hole mobility across hole transfer layer which was derived from the delayed response time of Transient EL.

We successfully developed 256Mb Phase Change Random Access Memory (PRAM) based on 0.10μ m-CMOS technologies using ring type contact. The writing current with uniform CD process variation of Bottom Electrode Contact (BEC) was achieved by improving CMP process and developing core dielectric material. Also, the ring type contact scheme provided strong reliability such as the cycling endurance and data retention time for 256 Mb high density PRAM.

We studied the characteristics of organic light emitting diode (OLED) devices containing two-dimensional (2D) SiO2∕SiNx photonic crystal (PC) layers. The finite-difference time-domain (FDTD) method was employed for the design and analysis of the PC OLED. Based on the design parameters derived from the FDTD calculations, a 2D PC layer was introduced on the glass substrate of a typical OLED structure by two-step irradiated hologram lithography and reactive ion etching. Experiments showed that incorporation of the PC layer improved the light extraction efficiency by over 50% compared to the conventional OLED, without noticeable degradation in electrical characteristics, under typical operating conditions. This improvement originates from the liberation of the photons trapped in the high-index guiding layers.

This work was fully supported by the Corporate Research & Development Center of Samsung SDI Co.Ltd.

As the capacitor size greatly decreases from 1.44 in 4Mb to 0.44 w m 2 in 32Mb FRAM, the hydrogen-damage is severely increased, thus giving rise to the difficulty in protecting the ferroelectric capacitor from the hydrogen attack by using conventional encapsulating barrier layers (EBL). Therefore, it is strongly required to reduce the hydrogen-induced degradation of very small ferroelectric capacitor during the backend integration process. In this paper, we developed double EBL technology by covering whole ferroelectric capacitors again after the Cap-EBL process. The Al 2 O 3 ILD-EBL layer was prepared again after depositing inter-layer dielectrics (ILD) layer, thus eliminating further hydrogen damage during inter-metal dielectrics (IMD) process. Using the double EBL technology, the fully integrated ferroelectric capacitor for 32Mb FRAM exhibits excellent ferroelectric properties such as remnent polarization of 15 w C/cm 2 at 3V. As a result, novel hydrogen-damage free 0.25 w m 15F 2 32Mb FRAM was success...

A ultraviolet (UV) process is commonly used in fabricating memory devices such as DRAM and SRAM without degrading the memory properties. However, in high density FRAM, the effect of UV light on ferroelectric properties has never been confirmed in real functional FRAM devices FRAM. Therefore, in this paper, we investigated the UV effect on ferroelectric properties and established an optimal back-end process for 1T1C 4Mb FRAM. It was found that the UV light illumination has strong influence on the hysteresis loop of ferroelectric capacitors. The polarization of the capacitor decreased and coercive voltage shifted after exposure to the UV light. It might be attributed to the fact that UV light generates free space charges in the ferroelectric layer and these charges are trapped at the electrode/ ferroelctric interface of the ferroelectric capacitor.

Both luminous efficiency and lifetime in blue fluorescence organic light emitting devices (OLEDs) have been improved by modified HTMs with higher LUMO energy levels. The LUMO energy levels of HTM were increased by modifying substituent in HTM molecules. Two HTMs containing ortho and meta biphenyl substituent and one HTM containing thiophene substituent were synthesized via palladium catalyzed amine coupling reactions to compare with a para biphenyl substituent HTM-1 as a standard molecule. According to TDDFT calculations, these three modified HTMs showed 0.05-0.15 eV higher LUMO energy levels compared to the para biphenyl substituent HTM-1. The luminous efficiency and the lifetime (LT90) of OLEDs using HTM-2 at 500 cd/m2 have been enhanced up to 20 % and 52 %, respectively, compared to the standard device using HTM-1.

Utilizing the near- to far-field transformation based on the 3-D finite difference time domain (FDTD) method and Fourier transformation, the far-field profile of a photonic crystal organic light emitting diode is studied to understand the viewing angle dependence. The measured far-field profiles agree well with those of the simulation. The enhancement of the extraction efficiency in excess of 60% is observed for the optimized photonic crystal pattern.

We propose and demonstrate weak-microcavity organic light-emitting diode (OLED) displays that deliver both a high light-extraction efficiency and wide viewing-angle characteristics. A single pair of low- and high-index layers is inserted between indium tin oxide (ITO) and a glass substrate. The electroluminescent (EL) efficiencies of discrete red, green, and blue weak-microcavity OLEDs (WMOLEDs) are enhanced by 56%, 107%, and 26%, respectively with minimal changes viewing angle and EL spectra characteristics. The color purity is also improved for all three colors. Moreover, we fabricated full-color 128×160 passive-matrix bottom-emitting WMOLED displays to prove their manufacturability. This design is realized by simple one-step 20-nm etching of the low-index layer of red/green subpixels. The EL efficiency of white color in the WMOLED display is 27% higher than that of a conventional OLED display.

We propose and demonstrate weak-microcavity organic light-emitting diode (OLED) displays with improved light-extraction and viewing-angle characteristics. A single pair of low- and high-index layers is inserted between indium tin oxide (ITO) and a glass substrate. The electroluminescent (EL) efficiencies of discrete red, green, and blue weak-microcavity OLEDs are enhanced by 56%, 107%, and 26%, respectively, with improved color purity. Moreover, full-color 128×160 passive-matrix bottom-emitting OLED displays are fabricated by employing low-index layers of two thicknesses. As a display, the EL efficiency of white color was 27% higher than that of a conventional OLED display.

With respect to the operation of a Phase-change Random Access Memory (PRAM or PcRAM), we studied the effect of the contact between the electrode metal and the chalcogenide glass, N2 doped Ge2Sb2Te5 in this report. We investigated a change of the resistance-programming current pulse (R-I) curve varying the contact size and the electrode material. Also we tested the surface oxidation of the electrode. We found that the programming current, the resistance of the programmed state (“RESET”) and the erased state (“SET”) were highly dependent on the above parameters. These results are presented and a more effective way to the high density PRAM will be proposed.

In this paper, an etching damage-free 4 Mb ferroelectric random access memory (FRAM) integration technology was for the first time developed using ferroelectric (FE) hole capacitor structure. Since the PZT capacitors are not etched, no etching damage was generated in the novel capacitor structure. The etching process issue, which is one of most critical obstacles for scaling down FRAM device, is completely resolved by using this novel FE hole structure. Therefore, the novel integration technology strongly promises to provide a reliable scaling down of FRAM device beyond 0.25 /spl mu/m technology generation.

14.1” qFHD quarter Full High Definition Transparent Active Matrix Organic Light Emitting Display AM OLED was developed with the well known and reliable technology based on LTPS Low Temperature Poly Silicon backplane. The key concept of the transparent AM OLED display lies on the seethrough window on each pixel so that the objects across the device can be seen. In the design of pixel structure, functional separation of light emitting area and seethrough area was realized on the different regions. The features of transparency and transmitted image quality were investigated and optimized in the design of the pixel structure. Up to 38% transparency of the prototype panel was accomplished with the high transparent cathode material which transmittance was more than 75%. LTPS based Active Matrix and Top emission OLED structure was used for the prototype to provide wide range of color expression, more than 100% of color gamut.

We report on the concept of a thin film wire-grid polarizer (WGP) with optically dual characteristics by introducing a nano-patterned graded metal-dielectric composite-material layer. The Ti-SiO2 composite layer with a depth profile of a gradually-varied composition ratio shows an absorptive feature due to the elimination of an optical interface between a metal and a glass substrate, while the metal side of the WGP gives a reflective character. The unprecedented optically-bifacial thin-film WGP with the 144 nm-period straight-line patterns of a 100 nm-thick Ti-SiO2 composite layer and a 185 nm-thick Al layer shows the exceptionally low reflectance below 15 % from the absorptive side and the high polarization extinction ratio (PER) of over 500 at 550 nm, which is acceptable for use as various display applications such as AMOLEDs and LCDs.

The light extraction characteristics of low-index spin-on-glass (SOG)-assisted, planarized photonic crystal organic light-emitting diodes (PC OLEDs) are reported. The light extraction efficiencies of planarized two-dimensional (2D) SiNx∕SOG PC OLEDs (type II) and 2D SiNx∕SOG PC OLEDs with an additional high-index SiNx layer (type III) are significantly better under typical operating conditions than those of the first generation of 2D SiO2∕SiNx PC OLEDs (type I). The enhancements in the extraction efficiencies of type-II and type-III PC OLEDs are about 63% and 85%, respectively, with respect to those of conventional OLEDs with indium tin oxide layers of identical thicknesses. These improvements in extraction efficiencies are attributed not only to the liberation of the photons trapped in the high-index guiding layer but also to a reduction in the surface plasmon contribution.