Zhuangde Jiang

The design and analysis of beam-membrane structure sensors for micro-pressure measurement

This paper reports the design and analysis of a type of piezoresistive pressure sensor for micro-pressure measurement with a cross beam-membrane (CBM) structure. This new silicon substrate-based sensor has the advantages of a miniature structure and high sensitivity, linearity, and accuracy. By using the finite element method to analyze the stress distribution of the new structure and subsequently deducing the relationship between structural dimensions and mechanical performances, equations used to determine the CBM structure are established. Based on the CBM model and our stress and deflections equations, sensor fabrication is then performed on the silicon wafer via a process including anisotropy chemical etching and inductively coupled plasma. The structures merits, such as linearity, sensitivity, and repeatability, have been investigated under the pressure of 5 kPa. Our results show that the precision of these equations is ±0.19%FS, indicating that this new small-sized structure offers easy preparation, high sensitivity, and high accuracy for micro-pressure measurement.

Incorporation of beams into bossed diaphragm for a high sensitivity and overload micro pressure sensor

The paper presents a piezoresistive absolute micro pressure sensor, which is of great benefits for altitude location. In this investigation, the design, fabrication, and test of the sensor are involved. By analyzing the stress distribution of sensitive elements using finite element method, a novel structure through the introduction of sensitive beams into traditional bossed diaphragm is built up. The proposed configuration presents its advantages in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the equations about the sensor. Nonlinear optimization by MATLAB is carried out to determine the structure dimensions. The output signals in both static and dynamic environments are evaluated. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the fabrication process is discussed. Experimental results demonstrate the sensor features a high sensitivity of 11.098 μV/V/Pa in the operating range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure to promise its survival under atmosphere. Due to the excellent performance above, the sensor can be applied in measuring the absolute micro pressure lower than 500 Pa.

The novel structural design for pressure sensors

Purpose – The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.Design/methodology/approach – A kind of novel piezoresistive micro‐pressure sensor with a cross‐beam membrane (CBM) structure is designed based on the silicon substrate. Through analyzing the stress distribution of the new structure by finite element method, the model of structure is established and compared with traditional structures. The fabrication is operated on silicon wafer, which applies the technology of anisotropy chemical etching and inductively coupled plasma.Findings – Compared to the traditional C‐ and E‐type structures, this new CBM structure has the advantages of low nonlinearity and high sensitivities by the cross‐beam on the membrane, which cause the stress is more concentrated in sensitive area and the deflections that relate to the linearity are decreased.Originality/value – The paper provides the first empirical reports on the new piezor...

Fabrication and Structural Design of Micro Pressure Sensors for Tire Pressure Measurement Systems (TPMS)

In this paper we describe the design and testing of a micro piezoresistive pressure sensor for a Tire Pressure Measurement System (TPMS) which has the advantages of a minimized structure, high sensitivity, linearity and accuracy. Through analysis of the stress distribution of the diaphragm using the ANSYS software, a model of the structure was established. The fabrication on a single silicon substrate utilizes the technologies of anisotropic chemical etching and packaging through glass anodic bonding. The performance of this type of piezoresistive sensor, including size, sensitivity, and long-term stability, were investigated. The results indicate that the accuracy is 0.5% FS, therefore this design meets the requirements for a TPMS, and not only has a smaller size and simplicity of preparation, but also has high sensitivity and accuracy.

Uncertainty estimation in measurement of micromechanical properties using random-fuzzy variables

Instrumented indentation testing mechanical properties of small volume materials can be affected by various factors during the measurement process, either in random or nonrandom characteristics, which can induce much uncertainty in the evaluation results. The traditional uncertainty estimation method, which is based on probability theory, is ineffective for the cases where some nonrandom effects are present. In this article, uncertainty estimation in measurement of hardness and elastic modulus by tester for micromechanical properties associated with random-fuzzy variables (RFVs) is presented. Uncertainty estimation results from both the traditional and RFV methods are derived and compared. Results show that the measurement uncertainties in hardness and elastic modulus can be effectively expressed in terms of RFVs under different levels of confidence, and all possible influencing effects on the uncertainties can be involved.

High temperature and frequency pressure sensor based on silicon-on-insulator layers

Based on silicon on insulator (SOI) technology, a novel high temperature pressure sensor with high frequency response is designed and fabricated, in which a buried silicon dioxide layer in the silicon material is developed by the separation by implantation of oxygen (SIMOX) technology. This layer can isolate leak currents between the top silicon layer for the detecting circuit and body silicon at a temperature of about 200 °C. In addition, the technology of silicon and glass bonding is used to create a package of the sensor without internal strain. A structural model and test data from the sensor are presented. The experimental results showed that this kind of sensor possesses good static performance in a high temperature environment and high frequency dynamic characteristics, which may satisfy the pressure measurement demands of the oil industry, aviation and space, and so on.

Surface plasmon enhanced photoluminescence of ZnO nanorods by capping reduced graphene oxide sheets.

A hybrid structure of reduced graphene oxide (rGO) sheets/ZnO nanorods was prepared and its photoluminescence intensity ratio between the UV and defect emission was enhanced up to 14 times. By controlling the reduction degree of rGO on the surface of ZnO nanorods, the UV emission was tuned with the introduction of localized surface plasmons resonance of rGO sheets. The suppression of the defect emission was ascribed to the charge transfer and decreased with the distance between the rGO and ZnO nanorods.

Low-temperature remote plasma-enhanced atomic layer deposition of graphene and characterization of its atomic-level structure

Graphene has attracted a great deal of research interest owing to its unique properties and many potential applications. Chemical vapor deposition has shown some potential for the growth of large-scale and uniform graphene films; however, a high temperature (over 800 °C) is usually required for such growth. A whole new method for the synthesis of graphene at low temperatures by means of remote plasma-enhanced atomic layer deposition is developed in this work. Liquid benzene was used as a carbon source. Large graphene sheets with excellent quality were prepared at a growth temperature as low as 400 °C. The atomic structure of the graphene was characterized by means of aberration-corrected transmission electron microscopy. Hexagonal carbon rings and carbon atoms were observed, indicating a highly crystalline structure of the graphene. These results point to a new technique for the growth of high-quality graphene for potential device applications.

3D MEMS Design Method via SolidWorks

To enable MEMS designers to create fabrication-ready models of MEMS devices in an intuitive environment, this paper describes a MEMS design strategy that uses parameterized three-dimensional (3D) part features to construct geometric models of MEMS devices and then generates mask-layouts and process flows automatically. SolidWorks, an outstanding 3D design tool, is utilized to build the 3D model of the MEMS device. Most frequently-used 3D MEMS part features are created in SolidWorks and saved to a user database through Application Programming Interfaces (APIs) of SolidWorks. When designing a MEMS device, the designer develops its 3D model by selecting 3D part features from the database, and then uses Finite Element Analysis (FEA) to refine the model until it exhibits the desired characteristics. Next, the model is used to generate mask-layouts and process flows. Finally, it is necessary to verify whether the mask-layouts and process flows are generated correctly by reconstructing them into a 3D geometric model and comparing it to the designed 3D model. If there are differences between them, the designer is supposed to modify the mask-layouts and process flows until they can result in the desired shape of the MEMS device.

Rigorous electromagnetic test of super-oscillatory lens.

Thus far, the vector field of light probed by a nanostructured super-oscillatory lens (SOL) has mostly been studied by approximate theoretical means. Here the first rigorous electromagnetic (EM) test has been presented through an established electromagnetic model solved by the three-dimensional (3D) finite-difference time-domain (FDTD) method. It is found through comparisons that scalar/vectorial theories currently used for designing the metal-film-coated SOL can effectively predict the on-axis intensity behind a SOL simulated by FDTD for both linearly and circularly polarized beams; however, they cannot reflect the true 3D EM vector field distribution particularly for the linearly polarized beam and imprecise results for the total electric energy density have appeared in certain transverse planes, e.g. a relative error as high as 26% is produced for the size of the main focus behind a SOL of 14 μm large in diameter. Besides, it is found that current theories cannot be used for designing the glass-etched phase-type SOL.