Rohlfing Franziska

Characterization of LPCVD SiC thin films at elevated temperatures for robust MEMS sensor applications

In this work we present a systematic characterization of the mechanical properties of thin-film silicon carbide electrodes and released structures as components of a μ-contact type combustion pressure sensor. We developed, fabricated and successfully applied designated MEMS test structures for the determination of the Youngs modulus, residual stress, stress gradient and coefficient of thermal expansion of thin SiC films. In particular, a novel model, describing the capacitance-voltage characteristic of the test structures, has been developed and used for the purely electrical determination of the Youngs modulus and stress gradient of the SiC layers.