The validity of a novel, direct and convenient method for micromechanical property measurements by beam bending using a nanoindenter has been demonstrated. In the deflection of microbeams, the influence of the indenter tip pushing into the top of the microbeams and the curvature across its width must be considered. The elastic deflection of a polysilicon microcantilever beam will vary linearly with the force. Thus, Young's modulus of the beam determined from the slope of this linear relation is 156 Gpa 92.9-6.3%. The size effects of the manufactured component on Young's modulus and strength of polysilicon microcantilever beams were measured. This result shows that the rupture strengths of polysilicon beams show size effect on the effective volume and surface area of the specimens. The rupture strength of each sample decreased with increasing the specimen effective volume and surface area, but increased with increasing the surface-to-volume ratio. The defect that initiates fracture is often on the surface of the specimen. In such cases the size effect can be traced back to a surface-to-volume ratio as the governing parameter.

A new microtensile test device using a magnetic-solenoid force actuator was developed to evaluate the mechanical properties of microfabricated polysilicon thin films that were 100-660mm long, 20-200mm wide, and 2.4-mm thick. It was found that the measured average value of Young's modulus, 164 GPa

The nanoindentation fracture of multilayer hard coatings of TiNrTi C,N.rTiC, Al2O3rTiCrTi C,N.rTiC, TiNrTi C,N.rTiCrTi C,N.rTiC and TiNrTi C,N.rTiCrTi C,N.rTiCrTi C,N.rTiC, deposited on cemented carbide using a CVD technique was studied. Based on an analysis of the energy released in cracking, the calculated fracture toughness values of these coatings were 2.18, 1.74, 3.40 and 3.90 MPa m1r2, respectively. Both load-penetration depth and loadl penetration depth squared plots have been demonstrated to be necessary if a more complete understanding of the coating system behaviour is to be gained. The interfacial failure and the critical load of interfacial failure of these coatings were also discussed. A step was found in the forcel displacement curves at the onset of coating fracture. A straight line segment in the oad-penetration depth squared curves was discussed. The hardness, fracture toughness and anti-wearability of these coatings were compared. The results show that the fracture toughness and anti-wearability are getting higher with the layers increasing.

The increasing use of small micromechanical devices and advanced sensors has led to concern about the failure modes and reliability of these structures. The enormous promise will not materialize without substantial progress in overcoming the stiction, friction and wear associated with such devices and understanding the mechanical behavior of MEMS materials and structures. Self-assembled monolayers (SAMs) are release and anti-stiction coatings for MEMS. In this paper, the anti-stiction properties of octadecyltrichlorosilane (OTS) SAM were calculated. The microtribological properties of OTS SAM were investigated with a ball-on-flat microtribometer. The influence of OTS SAM on the mechanical properties of micromachined polysilicon films for MEMS was investigated with an accurate evaluation using the microtensile test device. It was concluded that the OTS SAM has good anti-stiction properties and low friction coefficients. The hydrophobic property of OTS is the main factor leading to an increase in the average fracture strength of micromachined polysilicon up to 32.46%. Thus, the operational stability and lifetime of MEMS can be raised when coated with self-assembled monolayers.

For the purposes of pressure measurement at high temperature in oil drilling industry as well as in other industrial measurement and control systems, the strain gauge chip of piezoresistive pressure sensor is designed based on separation by implanted oxygen (SIMOX) SOI (silicon on insulator) technology, and then fabricated in the micro-machining work bay. Some kinds of sensor mechanical structures are designed for different customers and conditions. The thermal coefficients of expansion (TCE) mismatches between different materials within the highpressure sensor system are investigated. The sensor is fabricated successfully by using high temperature packaging process. The temperature coefficient of sensitivity (TCS) and temperature coefficient of offset (TCO) compensation circuitry is demonstrated. Based on experimental data, the sensor is tested with high accuracy and good stability.