High temperature nanoscale mechanical property measurements

A depth sensing indentation instrument widely used for measuring the small scale mechanical properties of thin films and surfaces has been modified fo r operation at elevated temperatures. The essential feature permitting this development is the vertical orientation of the specimen, which allows the heated zone to be placed above the high sensitivity displacement transducer . In the present work, small scale hardness and elastic modulus measurement s were performed on glass, gold, and single crystal silicon at room tempera ture and 200 degrees C. The results show that at 200 degrees C the hardness and elastic modulus of soda lime glass and gold are lower than at room tem perature, as anticipated. In contrast, indentation testing of Si(100) at 20 0 degrees C produced a similar hardness value to that obtained at room temp erature, although the modulus was again reduced, from 140.3 to 66.0 GPa. In addition, the well known 'pop out' event, which is observed during unloadi ng of a silicon indentation at room temperature, disappeared at 200 degrees C. (C) 2000 IoM Communications Ltd.