Fabrication and characterization of a piezoelectric gallium nitride switch for optical MEMS applications

The utilization of gallium nitride (GaN) in the area of microelectronics continues to increase due to the advantages it offers over other semiconductors. This paper presents GaN as a candidate material well suited for novel microelectromechanical systems (MEMS). The potential of GaN for MEMS is demonstrated via the design, analysis, fabrication, testing and characterization of an optical microswitch device actuated by piezoelectric and electrostrictive means. The piezoelectric and electrostrictive properties of GaN and its differences from common piezoelectrics are briefly discussed before touching upon the device configuration used to implement the microswitch device. Subsequently, the development of two recent fabrication technologies, photoelectrochemical etching and bias-enabled dark electrochemical etching, used to realize the three-dimensional device structure in GaN are described in detail. Lastly, an ultra-low-cost, laser-based, non-contact approach to test and characterize the microswitch device is described, followed by the device testing results.