Measurement On The Young's Modulus Of SiC Thin Films Based On Four Fixed-edge Rectangular Films Structure

SiC which keeps excellent mechanical properties in the environment of high temperature, strong corrosion and intense radiation, is the preferred material in bad environment. At present, SiC's fabrication process is not very perfect, and the Young's modulus differs when it's fabricated by different technique. So the Young's modulus of SiC thin films needs to be measured when they are fabricated. Most methods to micro-structure mechanical properties need to machine the samples, but SiC has a very stable chemical property, so it's very difficult to be etched. This paper measured SiC's micro-scale Young's modulus through measuring the elastic coefficient of four fixed-edge rectangular SiC films based on rectangular films theory. It doesn't need to etch the SiC and can measure the Young's modulus quickly. The details are as follows:1. In the aspects of mechanical theory, this paper based on couple stress theory, researched the mechanical properties of four fixed-edge square films, and get the solutions of deflection Young's modulus.2. In the aspects of process route, this paper explored square SiC thin films' process route. It's very difficult to make SiC thin films because its thickness is only 3.89?m and it's very breakable. In this paper, KOH and TMAH were used to process the sample respectively. And finally two pieces of SiC square thin films were gotten successfully.3. In the aspects of the measuring of mechanical properties, this paper measured SiC's Young's modulus and the through measuring the four fixed-edge square SiC films' midpoint elastic coefficient by AFM. Firstly, measure Si's Young's modulus to prove the reliability of this method. The Young's modulus of Si measured by this method is 141.9GPa when the standard is 130 GPa. It shows that this method is reliable. The Young's modulus of the two pieces of SiC square thin films are 79.7±6.10 GPa and 61.7±16.28 GPa. The SiC used in this paper has a rough crystal structure and its Young's modulus is smaller than those measured by conventional study. It shows that in the micro-scale, materials' crystal quality influences its mechanical properties seriously, and the SiC thin films' fabrication process need to be improved.