Method for a fast measurement of built-in voltage inside closed cavity MEMS-devices

A method to measure built-in voltages on the material interfaces in capacitive MEMS-devices inside closed cavities is presented. The method is based on a vibrating capacitor (Kelvin-probe) principle and it can even be used to measure closed cavity samples. The suggested set-up is tested by measuring various capacitive accelerometers and the results are compared with those obtained from capacitance–voltage (C–V) measurements. The potential of the method for high-speed measurements is explored by demonstrating an accurate determination of built-in voltages by measuring only a few data points for a device due to a very highly linear response of the method.