While more complex levels of integration are the future trend of MEMS technology, the present state-of-the-art is more modest and usually involves a single discrete microsensor, a single discrete microactuator, a single microsensor integrated with electronics, a multiplicity of essentially identical microsensors integrated with electronics, a single microactuator integrated with electronics, or a multiplicity of essentially identical microactuators integrated with electronics.
Nevertheless, as MEMS fabrication methods advance, the promise is an enormous design freedom wherein any type of microsensor and any type of microactuator can be merged with microelectronics as well as photonics, nanotechnology, etc. A surface micromachined resonator fabricated by the MNX.
This device can be used as both a microsensor as well as a microactuator. This vision of MEMS whereby microsensors, microactuators and microelectronics and other technologies, can be integrated onto a single microchip is expected to be one of the most important technological breakthroughs of the future. This will enable the development of smart products by augmenting the computational ability of microelectronics with the perception and control capabilities of microsensors and microactuators. Microelectronic integrated circuits can be thought of as the "brains" of a system and MEMS augments this decision-making capability with "eyes" and "arms", to allow microsystems to sense and control the environment.
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Sensors gather information from the environment through measuring mechanical, thermal, biological, chemical, optical, and magnetic phenomena. The electronics then process the information derived from the sensors and through some decision making capability direct the actuators to respond by moving, positioning, regulating, pumping, and filtering, thereby controlling the environment for some desired outcome or purpose.
Furthermore, because MEMS devices are manufactured using batch fabrication techniques, similar to ICs, unprecedented levels of functionality, reliability, and sophistication can be placed on a small silicon chip at a relatively low cost. MEMS technology is extremely diverse and fertile, both in its expected application areas, as well as in how the devices are designed and manufactured. Already, MEMS is revolutionizing many product categories by enabling complete systems-on-a-chip to be realized.
Nanotechnology is the ability to manipulate matter at the atomic or molecular level to make something useful at the nano-dimensional scale. Basically, there are two approaches in implementation: the top-down and the bottom-up. In the top-down approach, devices and structures are made using many of the same techniques as used in MEMS except they are made smaller in size, usually by employing more advanced photolithography and etching methods.
The bottom-up approach typically involves deposition, growing, or self-assembly technologies. The advantages of nano-dimensional devices over MEMS involve benefits mostly derived from the scaling laws, which can also present some challenges as well. An array of sub-micron posts made using top-down nanotechnology fabrication methods.
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The MEMS Module includes dedicated physics interfaces for thermal stress computations with extensive postprocessing and visualization capabilities, including stress and strain fields, principal stress and strain, equivalent stress, displacement fields, and more. There is also tremendous flexibility to add user-defined equations and expressions to the system. For example, to model Joule heating in a structure with temperature-dependent elastic properties, simply enter in the elastic constants as a function of temperature — no scripting or coding is required.
When COMSOL compiles the equations, the complex couplings generated by these user-defined expressions are automatically included in the equation system.
Mechanics of Microelectromechanical Systems - Nicolae Lobontiu, Ephrahim Garcia - Google книги
The equations are then solved using the finite element method and a range of industrial strength solvers. Once a solution is obtained, a vast range of postprocessing tools are available to interrogate the data, and predefined plots are automatically generated to show the device response. COMSOL offers the flexibility to evaluate a wide range of physical quantities, including predefined quantities like temperature, electric field, or stress tensor available through easy-to-use menus , as well as arbitrary user-defined expressions.
The Fluid-Structure Interaction FSI multiphysics interface combines fluid flow with solid mechanics to capture the interaction between the fluid and the solid structure.
Solid Mechanics and Laminar Flow user interfaces model the solid and the fluid, respectively. The FSI couplings appear on the boundaries between the fluid and the solid, and can include both fluid pressure and viscous forces, as well as momentum transfer from the solid to the fluid — bidirectional FSI.
The MEMS module has specialized thin film damping physics interfaces which solve the Reynolds equation to determine the fluid velocity and pressure and the forces on the adjacent surfaces. These interfaces can be used to model squeeze film and slide film damping across a wide range of pressures rarefaction effects can be included. Thin-film damping is available on arbitrary surfaces in 3D and can be directly coupled to 3D solids. The ease of integration of small piezoresistors with standard semiconductor processes, along with the reasonably linear response of the sensor, has made this technology particularly important in the pressure sensor industry.
For modeling piezoresistive sensors, the MEMS Module provides several dedicated physics interfaces for piezoresistivity in solids or shells. The Solid Mechanics physics interface is used for stress analysis as well as general linear and nonlinear solid mechanics, solving for the displacements. The MEMS Module includes linear elastic and linear viscoelastic material models, but you can supplement it with the Nonlinear Structural Materials Module to also include nonlinear material models.
You can extend the material models with thermal expansion, damping, and initial stress and strain features. In addition, several sources of initial strains are allowed, making it possible to include arbitrary inelastic strain contributions stemming from multiple physical sources. The description of elastic materials in the module includes isotropic, orthotropic, and fully anisotropic materials.
The Thermoelasticity physics interface is used to model linear thermoelastic materials.
It solves for the displacement of the structure and the temperature deviations, and resulting heat transfer induced by the thermoelastic coupling. Thermoelasticity is important in the modeling of high-quality factor MEMS resonators. Consequently, software specifically designed for MEMS simulation and modeling has never been more important.
Physics such as electromechanics, piezoelectricity, piezoresistivity, thermal-structure, and fluid-structure interactions can be modeled with the software. Design engineers can easily create models of common devices such as actuators, sensors, oscillators, filters, ultra sonic transducers, BioMEMS, and much more.
Try the software: Get a free 2-week trial by signing up for a workshop in a location near you. Siemens is a technology company working with electronics and electrical engineering in industry, energy, and healthcare. Microvisk Technologies develops and manufactures devices for measuring blood viscosity using the power of Micro Electronic Mechanical Systems MEMS and a radical new technique stemming from futuristic research on microtechnology.
Older hand-held devices on the market work by inducing a chemical reaction that is picked up by electrodes coated The model performs a static analysis on a piezoelectric actuator based on the movement of a cantilever beam, using the Piezoelectric Devices predefined multiphysics interface. Inspired by work done by V. Piefort and A.
Benjeddou, it models a sandwich beam using the shear mode of the piezoelectric material to deflect the tip. A capacitive pressure sensor is simulated. This model shows how to simulate the response of the pressure sensor to an applied pressure, and also how to analyze the effects of packing induced stresses on the sensor performance. This example shows how to set up a piezoelectric transducer problem following the work of Y.
Kagawa and T. The composite piezoelectric ultrasonic transducer has a cylindrical geometry that consists of a piezoceramic layer, two aluminum layers, and two adhesive layers. The system applies an AC potential on the electrode surfaces of An electrostatically actuated MEMS resonator is simulated in the time and frequency domains. The dependence of the resonant frequency on DC bias is assessed, and frequency domain and transient analyses are performed to investigate the device performance.
MEMS (micro-electromechanical systems)
The elastic cantilever beam is one of the elementary structures used in MEMS designs. This model shows the bending of a cantilever beam under an applied electrostatic load. EE and MBE Assessment Indicative only, please check the detailed course information. Offering Academic Unit. Department of Mechanical and Biomedical Engineering. Credit Units. Course Duration.