Polysilicon TFTs with the stacked gate oxide have been investigated by the variations of gate oxide process condition. The first layer of gate oxide was thermally grown thin oxide and the second layer was CVD oxide. With AFM measured the surface roughness of polysilicon which is believed to be a dominant factor for the device performance. Not only the thickness of thermally grown oxide, but also the temperature of CVD oxide process affects the interface roughness between polysilicon and gate oxide. The use of the stacked gate oxide which consists of 10nm thermal oxide and low temperature CVD oxide provided the improved performance of polysilicon TFT.
Electrical characteristics of polycrystalline silicon thin film transistors (TFTs) have been significantly improved using plasma hydrogenation. Different mole fractions of hydrogen diluted with nitrogen to perform the plasma passivation of TFTs were also investigated. The nitrogen-containing hydrogen plasma treatment showed better passivation effect than that for the pure hydrogen plasma. Oxygen plasma was also introduced to conduct the passivation effects and compared with the conventional hydrogen plasma. Pure oxygen plasma treatment showed a comparable or even better device improvement than pure hydrogen plasma passivation did. The results were attributed to the double-bond passivation and the grain growth enlargement after the subsequent annealing.
Microcrystalline silicon films were deposited by diluted-hydrogen method and hydrogen-atom-treatment method at 250℃ in a plasma enhanced chemical vapor deposition system and they were characterized by nuclear magnetic resonance. Raman spectroscopy, and optical bandgap measurements. One-mask a-Si:H thin film transistors (TFT's) were fabricated with those novel materials as the channel layer. The highest electron mobilities of the TFT's fabricated by diluted-hydrogen method and hydrogen-atom-treatment method were 1.23 and 1.04 cm^2/V・s, respectively without any thermal treatment steps.
We have studied the performance improvement of atmospheric pressure (AP) CVD a-Si thin film transistors. The N_2 plasma treatment and hydrogenation improve the performance of APCVD a-Si TFT significantly. The ion doped a-Si layer was used to make ohmic contact for the inverse staggered type TFTs. We obtained the field effect mobility of 1.05 cm^2/Vs and the threshold voltage of 6.3V. Therefore, we can increase the production throughput of a-Si TFT arrays by using APCVD a-Si and SiO_2 layers
Thin film transistors (TFTs) with various active polycrystalline silicon (poly-Si) layers fabricated using low temperature furnace annealing, high temperature furnace treatment, and laser recrystallization technique were investigated. Hydrogen plasma treatment for 30 min was performed to find the hydrogen passivation effects on the different poly-Si film structures. A dendritic structure was formed for the LPCVD amorphous-Si films after low-temperature furnace annealing. However, an equi-axised structure was obtained for the LPCVD silicon films deposited at 625℃. Consequently, TFTs With dendritic active layer obtained from the long-time, low-temperature annealing also possessed the better electrical characteristics in the passivation treatment. It is attributed to its larger grain sizes and the vague grain boundaries.
Recently the demand for large and fiat CRT and high definition CRT is remarkably increased. Then the development of high performance electron gun is essentially required. This paper describes a 3-Dimensional technique for the optimum design of the in-line electron gun. The boundary element method is used in the 3D electric field analysis, and the evolution stratege, which is a method for finding a global minimum, in the optimization. The method is applied to finding a minimum beam spot size on the exit of the gun, employing the major and minor radii of elliptic aperture as design variables.
In this paper, a procedure is described what had been done in constructing a simulation system for deflection yoke in CRT (Cathode-Ray-Tube) by using a commercial software package. First of all, the work of coil conductors establishment is presented, which is to simulate the winding of a true deflection yoke as the magnetic field source. Next, combined with a measured model of ferrite core, the field parameters, of both of line and frame deflection field, can be abstracted in this magnetic field computation system, which are absolutely needed for the electron-optics performance evaluation on the CRT screen. Simulation results are presented.
The market trend for color display tubes requires larger screen size (to prevent character too small), high resolution (that mean fine pitch, good spot and good convergence), beautiful and stable image, better contrast, and concerned about user comfort and safety. To meet such severe requirement, color display tubes have to keep upgrading technology.
For CAD/CAM CRT monitors, better convergence is one of the important issues to indicate the performance. Mis-convergence can be reduced electronically by adding suitable waveforms into multipoles (also called convergence coils), mounted on the neck of CRT. In this paper, we will explain several approaches that were developed in our orgination. These two-dimensional waveform generators used in monitors are : The bit-map approach, Digital convergence control I.C. ('DCONV'), and Translinear processor (or vector processor) . These approaches are distinguished in the following aspects: 1) The synchronization of the output waveform to the scanning process. 2) The order of complexity of the output waveform. After correction, mis-convergence will be beyond perception. Most of the discussion will be focused on the bit-map approach.
A new automatic alignment and inspection system product has been developed for monitor manufacturing. It characterizes a mechanical fixture with operating time less than 2 seconds. It uses a calibration method that enables accuracy of 0.4mm. It replaces the expensive color analyzer by the CCD camera and intelligent color software. The automatic alignment speed is 4 times that of the manual alignment. The investment return for monitor manufactures is expected to be very high.
Materials durability is an important factor in designing projection LCTV. A series experiment indicates that fluorinated and partial fluorinated liquid crystals both perform stable properties of electric resistance, threshold voltage, and saturation voltage under high temperature /high humid storage, thermal cycle, and low temperature storage tests. A noticeable curtailment of response time was observed for all the test sample in various environment tests. However, partial fluorinated liquid crystal losses more contrast ratio in thermal cycle test against full fluorinated liquid crystals.