Papers by Keyword: Self-Alignment

Abstract: A new concept for SiC MOSFET with a self-aligned channel is presented. The channel is defined by shallow source-JFET implantation into a counter-doped layer. This concept is verified by TCAD device simulations. It is shown that the method is applicable to fabrication of functional devices. The most critical parameter of the process is misalignment between channel and p-shield. Almost no change of electrical current in forward conduction state and the leakage current and electric field in the gate oxide in blocking state is observed for the misalignments below 400 nm.

Abstract: A comparison between self-aligned process (using lift-off) and Ni-SALICIDE used in fabrication of ohmic contacts for SiC Power MOSFET is done. Both processes are demonstrated for 3.3 kV SiC VDMOS transistors fabricated on 100 mm substrates. It is shown that the Ni-SALICIDE process with first silicidation at 500 °C does not degrade the electrical properties of silicon dioxide; particularly, a degradation of the interlayer dielectric between source and gate is not evident. Additionally, this first silicidation is found to have a positive impact on the specific resistance of contacts formed on p-type SiC using NiAl2.6% as an ohmic metal.

Abstract: The paper proposes a mechanical study of the self-centering mechanism of the bipolar prosthesis. This represents the fundamental principle of the bipolar construction, and relays on the offset between the inner and outer center of rotations of the bipolar head. In the paper, the kinematical aspects of the construction were recorded and explained by using five different offset values and keeping constant the femoral head diameter and the acetabular diameter. The simulations were conducted by imposing to the femoral head a linear movement in the vertical direction, similar to a reaction force that occurs when an implanted patient stands up. Two initial conditions were used for each geometric offset: one ideal, no friction and another more realistic by implementing friction coefficients at the sliding interfaces.

Abstract: An advanced LED multi-die-bonding integration using a fluidic self-assembly technique is proposed in the field of flip chip packages. Different form the conventional pick-and-place methods for a single LED die bonding, the fluidic approach is a relatively new design and a batch process, which can achieve not only die self-alignment but die self-assembly. Here, the size of LED die is 1-mm-square chip with the thickness of 0.3 mm. Due to the smaller size of LED die, the die-bonding process is still in need of finding a suitable approach and breakthrough. In this study, our design of fluidic self-assembly device is based on the experimental test and simulation results. The device design is the gas-flow channels with the magnetism. The width, height and length of each gas-flow channel are 1.1 mm, 0.5 mm, and 1 cm, respectively. With the restriction of the channel width, this structure design can control well to die self-alignment. In addition, the design of two circular structures in the channel can form a flat rim to achieve the die self-assemble. This mechanism of fluidic approach can be useful to the LED die self-alignment and self-assembly in the future batch processing.

Abstract: For the strong flurry interrupting, the body will suffer large swaying motion when it is in erecting state ,the output of its strapdown inertial navigation system (SINS) will be disturbed for the high gravitational. center of IMU, the conventional methods are difficult to achieve alignment rapidly and accurately, to solve this problem, an anti-interference self-alignment algorithm for SINS which under strong flurry is presented, which utilizes the continuous attitude update in inertial reference frame to record the attitude changes caused by sway interrupt to remove the angular interrupting, and uses the characteristics that the body exists a shake center whose speed is zero to remove the linear movement interrupting by acquiring the equivalent specific force of the shake center, and then uses the estimation of the initial attitude to determinate the attitude of the body. The simulation result show that the presented algorithm can accomplish alignment quickly even in the presence of strong flurry interference without coarse alignment phase.

Abstract: Fuzzy adaptive filter and H∞ filter are introduced to solve the problem of low filter performance, which comes from uncertain noise caused by seawave and high frequence vibrancy. First, basic principles of the fuzzy adaptive filter and H∞ filter are formulated. Second, state space model of self-alignment for SINS of the carrier craft is built. Finally, according to each character, a comparison on results that Kalman filter, fuzzy adaptive filter and H∞ filter are applied to alignment for SINS of the carrier craft is made. Simulation results show that although Kalman filter has definite robustness to external uncertainty noise, weak anti-jamming ability and bad filter performance make self-alignment failed. Fuzzy adaptive filter and H∞ filter have strong ability to suppress external uncertain noise and can obtain good filtering accuracy. They both can complete self-alignment. Filtering accuracy and rapidity of fuzzy adaptive filter are better than those of H∞ filter, while robustness and curve smoothness of H∞ filter are stronger than those of other filters.

Abstract: This paper presents a simple but effective method for inertial parameter identification with symmetrical trifilar pendulum and inertial measurement unit (IMU). An improvement upon conventional pendulum method is described by introducing IMU to identify the orientation of specimen by self-alignment, and then complicated equipment and experimental manipulation are not needed any more. Based on the excellent capacity of motion tracking, the IMU is also used for recording the characteristic of periodic movement by collected the information about acceleration and angular velocity. The main sources of identification errors are discussed from a set of examples. Then an experiment is carried out, and Fourier analysis is used to gain the oscillation period, which made the measurement much more convenient and accurate. The identification results are also presented by comparing with reference values computed from geometrical considerations, which proves the effectiveness of such method.

Abstract: In order to eliminate thermal deformation of large-scale precise machine tools caused by ambient temperature change, self-alignment design principle and key points are proposed for a large-scale precise machine tools, Self-alignment simulation experiment, machined parts experiment and compared results for self-alignment rail grinder and other similar products are analysed, the present analysis show that self-alignment rail grinder has many advangtages of good precision, straightness stability.