Measurements Of Young's Modulus Of Micro Scale SiC At High Temperature Based On Resonant Method

SiC,widely regarded as high temperature semiconductor material,receives more and more attention and application in the field of high temperature MEMS devices.At present,the research on the mechanical properties of micro scale SiC has achieved some progress,but there is still lack of a unified mechanical parameters standard,especially the temperature characteristics at high temperature.In this paper,the theoretical model is established based on composite cantilever,and the measurement system is built based on the resonant method,then the Young's modulus of the micro scale SiC thin film at different temperatures are achieved,so the temperature characteristics of that are studied.The specific contents include the following:1.Basic theory research: the calculation formula of the Young's modulus of the micro scale thin film is derived,the design criterion of the cantilever is discussed,the influence of film's thickness on the dimensional design of the composite cantilever is studied,and the dimensional parameter is analyzed by simulation.2.Measurement system built: the key of the system is the realization of high temperature environment,the incentive and detection in the environment.MCH ceramic heating plate as heating element and K type thermocouple as the temperature sensor are used to build the high temperature experiment environment and the actual temperature is measured by using the infrared thermometer;the cantilever is excited by mechanical vibration;the vibration frequency is measured by using the Polytec scanning vibrometer.3.Measurement system verification: the Young's modulus of single crystal silicon in the direction of [100] is measured.The result at room temperature is 132.5GPa which has 2.3% error compared with the reference value(129.5GPa),so the feasibility is proved.Then the Young's modulus at different temperatures is measured.4.Mechanical parameters test: the temperature characteristics of the Young's modulus of SiC thin film are studied.The results of two SiC samples,with the thickness of 5.3?m and 7.9?m,are 322.9±29.1GPa and 345.5±40.8GPa at room temperature.The Young's modulus of the micro scale SiC thin film are achieved at different temperatures,and the results shows that the Young's modulus shows a clear downward trend with the increase of temperature.