Electrically conducting ultrananocrystalline diamond for the development of a next generation of micro-actuators

• We have fabricated the first actuatable ultrananocrystalline based micro device.
• Nitrogen incorporation provides semiconducting property to the insulating diamond.
• The inertness of diamond eases the process of MEMS fabrication and releasing.
• We have mapped the temperature of the device in operation with Raman spectroscopy.
• We have monitored the displacement of the device with a maximum accuracy of 0.4 nm.

The potential of ultrananocrystalline diamond (UNCD) as a structural material for complex micro-electro mechanical systems (MEMS) is enormous due to its excellent chemical, mechanical and electrical properties, but it has so far not been extensively explored, mostly due to intrinsic stress problems. We have fabricated, for the first time, an actuatable MEMS device based on nitrogen-incorporated ultrananocrystalline diamond (N-UNCD), which is electrically conducting and has low intrinsic stress gradient. We characterized the N-UNCD and verified its semiconducting nature by looking at its thermal and electrical properties. Fifteen pairs of oriented slender beams (from 90 to 200 μm length) provide the driving force and are capable of generating a linear displacement on a central moving shuttle up to almost 2 μm. An ‘in-house’ built optical-based detection system was used to assess the motion of the actuator, with an accuracy of 0.4 nm. These results pave the way for development of diamond-based MEMS technology that could be applicable in many fields, including bio-medicine, optics, and sensors and actuators for space applications, where precision displacement is demanded along with robust materials, as well as general applications that require sliding surfaces.