Cheng-Fu Yang

Effects of Laser Annealing on the Electrical Characteristics of Dynamic Random Access Memory Using (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 Thin Films

(Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 (BSTZ) films are deposited on a Pt/Ti/SiO2/Si substrate at room temperature. KrF excimer laser annealing (ELA) technology is used to treat the BSTZ films, and the effect of laser energy power on the dielectric and electrical characteristics of ELA-treated BSTZ films is investigated in this study. Atomic force microscopy (AFM) observation shows that the BSTZ films decrease in roughness as the laser energy power increases. The leakage current density of ELA-treated BSTZ films markedly decreases as the laser energy power increases from 0 mJ/cm2 (no ELA treatment) to 200 mJ/cm2, and it decreases slightly as the laser power is further increased. The dielectric constants of ELA-treated BSTZ films first increase, reach a maximum, and then slightly decrease with increasing of laser energy power.

Cascade PI Controller Designs for Speed Control of Permanent Magnet Synchronous Motor Drive Using Direct Torque Approach

This paper presents a direct torque control (DTC) scheme using space vector modulation (SVM) to achieve high performance speed control of a permanent magnet synchronous motor. Based on the concept of a field-oriented control principle, a Proportional-integral (PI) flux controller is first established to achieve fast direct flux control and then cascade schemes of PI torque and speed controllers are presented to enhance the objective of speed control by the direct torque method. The effectiveness of the proposed control scheme under the load disturbance and parameter uncertainties is verified by simulation results.

Improved Optical Transmittance and Crystal Characteristics of ZnS:TbOF Thin Film on Bi4Ti3O12/Indium Tin Oxide/Glass Substrate by Using a SiO2 Buffer Layer

Bi4Ti3O12 thin films are deposited on indium tin oxide (ITO)/glass substrates using RF magnetron sputtering technology and are annealed at 675 °C in a rapid thermal annealing furnace in an oxygen atmosphere. The resulting films have high optical transmittances and good crystalline characteristics. ZnS:TbOF films are then deposited on the Bi4Ti3O12 films, causing the originally highly transparent specimens to blacken and to resemble a glass surface coated with carbon powder. The optical transmittance of the specimen is less than 15% under the visible wavelength range, and neither a crystalline phase nor a distinct ZnS grain structure is evident in X-ray diffractometer (XRD) and scanning electronic microscope (SEM). Secondary ion mass spectrometer (SIMS) analysis reveals the occurrence of interdiffusion between the ZnS and Bi4Ti3O12 layers. This suggests that one or more unknown chemical reactions take place among the elements Bi, S, and O at the interface during the deposition of ZnS:TbOF film on a Bi4Ti3O12/ITO/glass substrate. These reactions cause the visible transmittance of the specimens to deteriorate dramatically. To prevent interdiffusion, a silicon dioxide (SiO2) buffer layer 100 nm thick was grown on the Bi4Ti3O12/ITO/glass substrate using plasma-enhanced chemical vapor deposition (PECVD), then the ZnS:TbOF film was grown on the SiO2 buffer layer. The transmittance of the resulting specimen is enhanced approximately 8-fold in the visible region. XRD patterns reveal the ZnS(111)-oriented phase is dominant. Furthermore, dense, crack-free ZnS:TbOF grains are observed by SEM. The results imply that the SiO2 buffer layer sandwiched between the ZnS:TbOF and Bi4Ti3O2 layers effectively separates the two layers. Therefore, interdiffusion and chemical reactions are prevented at the interface of the two layers, and the crystalline characteristics of the ZnS:TbOF layer and the optical transmittance of the specimen are improved as a result. Finally, the dielectric constant of the stacked structure is lower than that of the single layer structure without SiO2, but the dielectric breakdown strength is enhanced.

Effect of Oxygen Concentration on Characteristics of Ba(Zr0.1Ti0.9)O3 Thin Films Deposited on Indium Tin Oxide/Glass Substrates

In this study, the perovskite Ba(Zr0.1Ti0.9)O3 (BZ1T9) ferroelectric thin films deposited on indium tin oxide (ITO)/glass substrates for applications in system-on-panel (SOP) devices are produced and investigated. The optimal sputtering conditions of as-deposited BZ1T9 thin films are an rf power of 160 W, a chamber pressure of 10 mTorr, a substrate temperature of 580 °C, and an oxygen concentration of 40%. The effect of oxygen concentration on the physical and electrical characteristics of BZ1T9 thin films is determined. For different oxygen concentrations, the thickness and deposition rate are calculated by scanning electron microscopy (SEM). From polarization versus electrical field curves, the 2Pr value and coercive field of BZ1T9 thin films are determined to be 7 µC/cm2 and 250 kV/cm, respectively. In addition, the maximum dielectric constant, leakage current density, and transmittance within the ultraviolet–visible (UV–vis) spectrum are investigated.

Electrical and Optical Characteristics of Bi4Ti3O12 Thin Film on Indium–Tin-Oxide/Glass

Thin films of bismuth titanate are deposited on indium–tin-oxide (ITO)/glass substrates by RF magnetron sputtering for 60 min at room temperature using a Bi4Ti3O12+4 wt % Bi2O3 ceramic target, and they are annealed at various temperatures ranging from 600 to 725 °C by a rapid thermal processing for 10 min. The experimental results indicate that the Bi4Ti3O12 films annealed at 675–700 °C exhibit superior electrical characteristics compared to those of other ferroelectric materials such as BaTiO3, PbTiO3, and SrTiO3 films, including a higher dielectric constant, a higher polarization charge density, and a more stable leakage current density. In addition, a high optical transmittance of the film was obtained at an annealing temperature of 650 °C. The results suggest that Bi4Ti3O12 thin film is a candidate worthy of consideration as the insulating layer material of AC thin film electroluminescence devices.

Modeling a Si homojunction SOI-Tunnel FET with configurable voltage difference on gates

The impact of gate voltage differences on the performance of the novel n-type silicon homojunction SOI-Tunnel FET is studied. Based on numerical simulation results using Synopsys Technology Computer-Aided Design (TCAD), the higher on-current and the ultra-low off-current are observed as compared to that of a conventional SOI-Tunnel FET. The analysis of energy band corroborates that gate voltage differences can revamp the potential barrier in the channel region, which can in turn modulate the drain current.

Investigation of a wheel-knife module with feedback torque signal for generation six to eight flat panel cutting

In this paper, we would investigate a wheel-knife module with feedback torque signal for generation six to eight flat panel cutting. The system of the investigated wheel-knife module was designed by using the servo type because thus type had the following figure merits. (1) The servo type could proceed with the stable cutting motion and its cutting depth would have a uniform value. (2) When the cutting process was carried out, the servo type could have smaller residual chippings. (3) The residual chippings on the cutting lines were more uniform and smaller than other system. The figure merit of the investigated system is that the signal can be feedback to the panel cutting platform, then we can immediately control the model and process of wheel-knife module via the control system of the panel cutting platform.

Investigation of an auto motion and high efficiency platform for generation six to eight flat panel

As the area of glass panel becomes larger and the thickness becomes thinner (from 0.5mm to about 0.3mm), the method for the load of glass panel under the mass-production will be changed to another method, for example by platform with auto load function. In this study, we investigated a platform for generation six (G6, 1850 × 1500 mm) to generation eight (G8, 2460 × 2160 mm). The investigated auto panel-cutting platforms had the human-machine interface which could be designed to have the function of choosing the different cutting area. The investigated platform has two special functions, which can be controlled by the human-machine interface. The first is the diagnosis model, which is used to choose the cutting area for the analysis of the fail problem. The second is the accepted goods and unaccepted goods (OK/NG) model. The area of cutting glass panels could be controlled by the computer-integrated manufacturing (CIM) program.

Design of the circularly polarized antenna on composite substrate

A 925 MHz circularly polarized (CP) antennas is designed and printed on (Ba0.8Sr0.2)(Ti0.9Znu)O3 (BSTZ)/Polyetherimide (PEI) composite substrates. A CP antenna with a simple structure is developed as the ultra high frequency (UHF) band radio frequency identification (RFID) reader application. In this study, it was demonstrated that the CP antenna fabricated on BSTZ/PEI substrate exhibited the better characteristics, low cost and less size than those fabricated on others substrate.

A switched-capacitor current-reused VCO with symmetrical differential outputs

In this paper, we present a modified topology to reduce influence degree of the device parameters on the circuit performances. In addition, the larger VCO gain (KVCO) brings about the worse phase noise [2]. Hence, the topology of switching capacitor is used to enhance the characteristics of phase noise by dividing the wanted frequency band into four sections.