Jc. Jiang et al., FABRICATION OF MICROMACHINED SILICON TIP TRANSDUCER FOR TACTILE SENSING, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 11(6), 1993, pp. 1962-1967
The tunneling vacuum diode was employed to construct a novel displacem
ent transducer for tactile sensing. High sensitivity of the emission c
urrent to variations of cathode-anode separation is the most important
feat re. The device was fabricated on a silicon wafer. The device com
ponents are a single tip or an array of tips made by wet etching, and
a metal anode diaphragm. Nitric acid-ammonium fluoride etchant is used
at room temperature to etch the silicon tips, with an easily controll
ed etch rate and excellent uniformity. A unique sacrificial layer tech
nique creates and controls the spacing between cathode tip and anode d
iaphragm. Highly sensitive responses of the device current to differen
t force loads on the anode diaphragm are presented.