K.C. Lin

The Effect of Ternary Material (Zr, Y, and O) High-k Gate Dielectrics

In this research, the Y2O3 layer is doped with the zirconium through co-sputtering and rapid thermal annealing (RTA) at 550°C, 700°C, and 850°C. Then the Al electrode is deposited to generate two kinds of structures, Al/ZrN/ Y2O3/ Y2O3+Zr/p-Si and Al/ZrN/ Y2O3+Zr/ Y2O3/p-Si. According to the XRD results, when Zr was doped on the upper layer, the crystallization phenomenon was more significant than Zr was at the bottom layer, meaning that Zr may influence the diffusion of the oxygen. The AFM also shows that the surface roughness of Zr has worse performance. For the electrical property, the influence to overall leakage current is increased because the equivalent oxide thickness (EOT) is thinner.

Adaptive Fuzzy Control of Two-Wheeled Balancing Vehicle

This paper proposes an adaptive fuzzy controller to balance a constructed two-wheeled vehicle at upright position. The dynamical model of the vehicle-LEGO Mind storms NXT is first established. Based on the model developed, an adaptive fuzzy controller is then illustrated. Adaptation laws are derived from the Lyapunov stability analysis, so that the system tracking performance and the error convergence can be assured in the closed-loop control system. Finally, we apply the PD (Proportional Derivative) controller and the proposed controller to balance the two-wheeled vehicle to compare the system performance.

Ferroelectric of HfO2 dielectric layer sputtered with TiN or ZrN for sandwich-like metal-insulator-metal capacitors

In this study, metal-insulator-metal (MIM) capacitors, which use HfO2 as the intermediate insulating layer, and TiN or ZrN as the upper/lower capping layers were fabricated to form the sandwich-like structures, i.e. Al/TiN/HfO2/TiN/Mo/p-Si and Al/ZrN/HfO2/ZrN/Mo/p-Si. The crystallization of high-k HfO2 thin-film is induced by high power impulse magnetron sputtering (HIPIMS) during the deposition of TiN and/or ZrN capping layers. The ferroelectric performance became better in both two structures as the thickness of metal nitride layer decreased. As the rapid thermal annealing (RTA) temperature after TiN layer deposition increased, the ferroelectric performance of the structure with TiN layer became better. On the other hand, the structure with ZrN layer exhibited opposite trends. According to X-ray diffraction (XRD) measurement, both TiN and ZrN layers offered stress and produced orthorhombic phase on HfO2 layer. Both two layers at any thicknesses also protected Mo layer from the invasion of Hf atoms. The structure with TiN layer exhibited a higher remanent polarization (Pr) value as the roughness of TiN layer increased. However, the higher the roughness that the structure with ZrN layer had, the worse the ferroelectric performance obtained.

Physically based modeling for stress assessment in MOS devices

For the purpose of boosting the performance of MOS devices, applying mechanical stresses to change the semiconductors band structure as well as to modulate the conduction mass is an effective and promising approach besides continuing to shrink the critical dimension of the devices. As a result of the stress impact on channel depends upon the layout-induced changes in topography of devices, it is therefore necessary to understand the physical behavior of strained silicon when the stressors such as silicon germanium (SiGe), silicon carbon (SiC) alloys and contact-etch-stop layer (CESL) are introduced. Accordingly, this paper presents a three-dimensional (3D) finite element analysis (FEA) combined with piezo-resistance mobility model to assess device performance in 40nm, 32nm technology node, and beyond. The presented simulation methodology is verified to be excellently reliable as is calibrated directly from electrical data. Based on the confirmed results of mobility gain, several important parameters, such as the recess depth of shallow trench isolation (STI) and channel width, are systematically investigated. It is noted that the stronger vertical stress (Szz) resulting from CESL is the main consequence of the reduction in channel width. Furthermore, the analytical results indicate that the extent of the mechanical effect of bending moment from a tensile CESL would be introduced into a fixed 100 nm narrow channel width of NMOSFETs when the concerned protruding gate width continues to increase.

Impact of stress induced by stressors on hot carrier reliability of strained nMOSFETs

In this study, the nMOSFETs with contact-etch-stop-layer (CESL) stressor and SiGe channel have been fabricated with a modified 90-nm technology. The performance of nMOSFETs and stress distribution in the channel region have been investigated. The hot carrier reliability of the SiGe-channeled nMOSFETs with various CESL nitride layers has also been extensively studied. In addition, the impact of stress induced by CESL stressor and SiGe-channel on hot-carrier reliability of the strained nMOSFETs has been analyzed through experimental measurements and stress simulation results.

The analysis of channel stress induced by CESL in N-MOSFET

The strained nitride capping layer (contact etch stop layer, CESL) is used as a stress booster that make transistor improvement. In this research, the n-MOSFET was simulated combining CESL tensile stressor. The stress in channel region for various part of CESL(CESL-top, CESL-lateral, CESL-bottom) were analysed and compared. The result of simulation explains how the CESL transmits the intrinsic stress to the channel. The relations between different CESL structures are discussed in this study.

Optimization of BiFeO3MFIS Capacitors Doped Niobium by Using Taguchi Method

In this study,MFIS (Metal/Ferroelectric/Insulator/Semiconductor) capacitors whose structure is Al/BFO+Nb/HfO2/p-Si are investigatedby using Taguchi Method. The effects of leakage current, memory window, and signal-to-noise ratio (S/N ratio) are discussed by different process conditions. As a result, the leakage current and memory window indicate the better performance on th same process condition. The better conditions of this MFIS capacitoroccur in rapid thermal annealing (RTA) at 700°C, 5W direct current (DC) power of Nb sputtering and 15 of argon-to-oxygen ratio for laekage current and memory window.Oxygen vacancies were reduced bydoping niobium (Nb) that Nb ions replace ferrum (Fe) ions with RTA at 700°C. The more Nb dopesthe more Nb ions replace Fe ions. Butthe excessive Nb induces to increase the leakage current and reduce the memory widow.

The analysis of the process-induced channel stress in N-MOSFET

This research analyzes internal stress in the N-MOSFET. The research has two parts. First, we explore the effect of N-MOSFET channel stress when CESL layer is not utilized. The dimensional effect of spacer upon channel stress in N-MOSFET with variant width of ONO (oxide, nitride, oxide) is compared. Second, with stress applied to CESL and the spacer stressor, long/short channel effects are analyzed. It is demonstrated that when the thickness of CESL and the height of gate increase, the channel stress under the gate dielectric layer becomes tensile, and the performance is improved in the short channel, resulting in the improved performance in the whole N-MOSFET. Therefore, better device characteristics can be expected through the approach disclosed in this paper.

The Simulation Analysis of MOSFET Channel Stress for Different Oxide/Nitride/Oxide (ONO) Spacer Thicknesses

It is demonstrated that the strained-Si can enhance the channel stress with the contact etching stop layer (CESL) stressor. In addition to CESL, this article also includes ONO spacer and investigates the impact of ONO spacer thickness on the channel stress. It is found that the channel stress increases when the nitride thickness of the ONO spacer increases. On the other hand, the stress distribution is simulated and analyzed for the devices with or without CESL stressor. Generally speaking, based on the simulation results, the channel stress of MOSFET devices increases when the nitride stressor of ONO spacer and/or CESL increases.

Adaptive Fuzzy Cerebellar Model Articulation Controller for two-wheeled robot

In this paper, an adaptive Fuzzy Cerebellar Model Articulation Controller (FCMAC) is proposed to control two-wheeled robot at upright position. The dynamical model of the robot, LEGO Mindstorms NXT, is derived from Lagrange of kinetic and potential energies. Based on the developed model, an adaptive FCMAC is then designed. Adaptation laws are derived from the Lyapunov stability analysis. According to the stability analysis, the developed FCMAC guarantees that the system tracking performance and the error convergence can be assured in the closed-loop system. Finally, to compare the system performances we apply the proposed FCMAC and the PID (Proportional Integral Derivative) controller to balance the two-wheeled robot.