A study on corrugated diaphragms for high-sensitivity structures

In this paper, the corrugated diaphragm technique is studied for applications to micromachined highly sensitive devices. Both static and dynamic behaviours of square corrugated diaphragms with various structural parameters and material properties are analysed using the finite-element method (FEM). The simulations show that very high performance (e.g., high mechanical sensitivity, small static deflection and high resonance frequency) of the diaphragms can be achieved using this technique. For the proposed corrugated diaphragms with anisotropically etched corrugations, much better reproducibility of the device performance can be expected. Different types of square diaphragm with rectangular corrugations have been fabricated using the silicon anisotropic etching technique and the optimized processes are presented. The measurements have shown reasonable agreement with the analyses. A capacitive pressure sensor is realized by the corrugation technique, with which sensitivity as high as 0.33% Pa-1 has been achieved.