Yoshiro Mikami

A new patterning process concept for large-area transistor circuit fabrication without using an optical mask aligner

A new concept to produce large thin film transistor liquid crystal displays (TFT-LCDs) without using an optical mask aligner is proposed which emphasizes patterning technology. Some experimental thin film transistors (TFTs) are fabricated according to the concept and operated like conventional transistors fabricated by using an optical mask aligner. The concept includes improvement of printing technology and development of a double-layer resist method. The latter method employs a printed ink pattern and a photoresist. This prevents contamination of thin films by metal impurities which affect electrical characteristics of the TFTs. A special gravure offset printing technology is proposed, composed of a large thixotropy valued UV ink, and a fine, precision etched glass intaglio. The experimental TFTs, with a designed minimum gate length of 10 /spl mu/m, have comparable electric characteristics to those of conventional poly-Si TFTs. >

Highly efficient and long life metal–insulator–metal cathodes

The authors improved the emission efficiency and lifetime of metal–insulator–metal cathodes. The drift of the diode current was suppressed by using a thinner tunneling insulator and a lower diode voltage. The cathode with a 7.9-nm-thick tunneling insulator kept the diode current stable at 0.5 A/cm2 for more than 20 000 h, although the initial emission efficiency declined from 2% to less than 0.5%, and the emission current drift increased. The decreased emission efficiency could be enhanced to more than 3% by mixing CsHCO3 into an Au/Pt/Ir multilayer top electrode.

Electronic energy states in Si-doped MgO for exoelectron emission

A generalized analytical method to determine the density of energy states of electron emission source (EES) is devised by using a thermal excitation and emission model for an exoelectron in the MgO layer and the emission time constants of the exoelectron extracted from experimental stochastic distributions of discharge delay time. When applied to Si-doped MgO, the emission time constant of the exoelectron from the Si EES becomes shorter at high temperature and at short time intervals due to thermal excitation. The density of energy states of the Si EES DSi(E) shows the main peak at 736 meV, a satellite peak at 601 meV, and broad energy structures over the range of 586–896 meV. The effective number of Si EES is 5.5 times larger than that in purified MgO. The excitation energy in a Si-doped MgO cluster with a crystal structure is obtained to be 0.83 eV by using the symmetry-adapted-cluster configuration interaction method and the Si EES contributes to exoelectron emission. The thermal excitation is governed...

Numerical analysis of density of energy states for electron‐emission sources in MgO

— An analytical method to determine the density of energy states of electron-emission sources (EESs) in chemical-doped MgO is described using a discharge probability model and a thermal excitation and emission model. The density of energy states for multiple types of EESs is represented by using a linear combination of Gaussian functions of which parameters are determined by the theoretical emission time constant of an exoelectron and statistical delay time ts extracted from experimental stochastic distributions of discharge delay time in plasma-display panels. When applied to Si-doped MgO, the effective number of Si EES is calculated to be 1.8 × 106 per cell. The average and standard deviations of activation energy have an energy level of 770 meV and a large value of 55 meV. In Si and H co-doped MgO, the high peak density of [H2−]0 appears at 550 meV. ts at the short time interval of 1 msec decreases and is independent of temperature due to exoelectron emission from the [H2−]0. The dependence of ts at a time interval of 10 msec on temperature becomes weak because the energy structure of the Si EES broadens significantly attributed to the electrostatic effects of the doped H atoms.

Emission Time Constant of Exoelectron and Formative Delay Time Analyzed by Using Discharge Probability Distribution

A discharge probability model is proposed to analyze the stochastic distribution of the discharge delay time. The distribution is described as a hybrid function between the exponential and Gaussian distributions and their characteristic properties, such as the emission time constant of an exoelectron and the average and standard deviations of the formative delay time. The calculated results of the probability of a successful discharge show a good agreement with the experimental results measured in plasma display panels. The analytical protocol allows the discharge delay time to be accurately separated into the statistical and formative delay times. A thermal excitation and emission model is devised to analyze the effective number and the activation energy of electron emission sources (EESs) in a MgO layer using the emission time constant of an exoelectron. The effective number of the EES, i.e., 3.79 × 105 per cell, decreases after a long time interval because of the thermal excitation; thus, the emission time constant increases significantly. The effective number of the EES after 1000 h of sustain discharge decreases to 2.07 × 104 per cell, which is 0.055 times that before the sustain discharge. This degradation is explained by 2.6-4.3 times of increase in the density of electron traps due to the ion sputtering of noble gases against the MgO surface. The emission time constant is found to decrease to 0.45 times when the wall voltage near the MgO surface is increased by 11 V, which demonstrates that the exoelectron emission can be controlled by the electric field.

Net sputtering rate due to hot ions in a Ne-Xe discharge gas bombarding an MgO layer

An analytical method is developed for determining net sputtering rate for an MgO layer under hot ions with low energy (<100 eV) in a neon-xenon discharge gas at near-atmospheric pressure. The primary sputtering rate is analyzed according to spatial and energy distributions of the hot ions with average energy, Ehi, above a threshold energy of sputtering, Eth,i, multiplied by a yield coefficient. The threshold energy of sputtering is determined from dissociation energy required to remove an atom from MgO surface multiplied by an energy-transfer coefficient. The re-deposition rate of the sputtered atoms is calculated by a diffusion simulation using a hybridized probabilistic and analytical method. These calculation methods are combined to analyze the net sputtering rate. Maximum net sputtering rate due to the hot neon ions increases above the partial pressure of 4% xenon as EhNe becomes higher and decreases near the partial pressure of 20% xenon as ion flux of neon decreases. The dependence due to the hot ne...

58.1: Invited Paper: Highly Efficient and Long Life MIM Cathodes for FEDs

The lifetime of MIM cathodes was lengthened to more than 20,000 hours by using a thinner tunneling insulator (6.9 nm), while the emission efficiency was enhanced to more than 3% by mixing CsHCO3 into a Au/Pt/Ir top electrode. The mechanism of long life and high efficiency will be discussed.

A 5-inch SVGA low-temperature poly-Si TFT-LCD with integrated digital interface driver

A high-resolution full-color LCD with integrated digital interface data driver is a strong candidate for mobile Internet appliances. This paper describes a low-temperature poly-Si (LTPS) TFT driver with 5-V/6-bit interface applicable to 5-inch SVGA LCDs. To reduce the driver area overhead, an architecture of multiplexed resistor-string D/A converter followed by synchronized signal distributor with alternative output voltages is demonstrated.

7.4: Reduction of Address‐Delay‐Time Degradation by Half‐Pitch Shifted Priming Cell Structure in AC‐PDPs

A half-pitch shifted priming cell structure to reduce address-delay-time degradation and lower power consumption has been developed. Discharge transition from a priming cell to a display cell occurred. The time constant of priming electron emission only from the priming cell did not degrade. Observed address-delay-time degradation in the display cell reduced.