Understanding the Lateral Tunneling Accelerometers and their Micromachining Processes

Micro Electro-Mechanical Systems (MEMS) have been revolutionizing the micro technology market with micromachining methodologies that make possible the micro fabrication of smaller, more efficient and economical devices. Lateral tunneling accelerometer has been characterized and fabricated to help a wide variety of industrial and commercial problems; one example is the air-bag deployment system in automobiles. What differentiates our Lateral tunneling accelerometer from other accelerometers is the ultra high sensitivity due to tunneling phenomena. In this research, characterization of different configuration of lateral tunneling accelerometers have been explored by interferometer techniques, which implies getting dynamical parameters of the system like frequency response, velocity, etc. The basic design of lateral tunneling accelerometer consists of three elements: proof-mass that moves relative to the substrate in response to an external stimulus, a sensor based on tunneling tip (quantum mechanics phenomena), and actuator based on capacitance, which could be a parallel plate or interdigitated comb fingers. These devices have been fabricated using the SCREAM 2003 where selectively parts of a Silicon-On-Insulator (SOI) wafer are etched away. The final released structures are coated with Ti-Pt-Au films in order for a current to tunnel across the separation gap between the tip and proof-mass.