LAUSR

PTB has developed a new contact based method for the traceable calibration of the normal stiffness of AFM cantilevers in the range from 0.03 N m(-1) to 300 N m-1 to the SI units based on micro-electro-mechanical system ( MEMS) actuators. This method is evaluated by comparing the measured cantilever stiffness with that measured by PTB's new primary nanonewton force facility and by PTB's microforce measuring device. The MEMS system was used to calibrate the stiffness of cantilevers in two case studies. One set of cantilevers for applications in biophysics was calibrated using the well-known thermal vibration method and the second set of cantilevers was calibrated by a cantilever manufacturer who applied an improved thermal vibration method based on calibrated reference cantilevers for the cantilever stiffness calibration. The comparison revealed a stiffness deviation of +7.7% for the cantilevers calibrated using the thermal vibration method and a deviation of +6.9% for the stiffnesses of the cantilevers calibrated using the improved thermal vibration method.