Fabrication and Characterization of Gallium Nitride Unimorphs for Optical MEMS Applications

The research outlined in this paper describes part of a larger effort to develop a novel branch of next-generation materials systems called Distributed Intelligent Materials Systems (DIMS) which incorporate actuation, sensing, electronics and communications modules as inherent parts of the material structure. Newer semiconductor materials that are under active research in the field of microelectronics are very well suited for such material systems. Gallium Nitride (GaN), a smart material, is pursued as a candidate material for such a system with a piezoelectrically actuated, optical microswitch being developed as the first prototypical device. This paper covers the unique electromechanical properties of GaN highlighting its differences from other piezoelectrics, the device configuration used to realize the switching device, followed by a description of and the progress made in using a nascent fabrication technology (PhotoElectroChemical Etching) used to realize the 3-dimensional device structure. Finally a low-cost, laser-based, non-contact approach to testing and characterizing the microscale device is described.