Cantilever-Based Dielectric Breakdown Mediated Ionization Pressure Sensor Using Poly Si Microtip

We report the development of cantilever-based cold cathode ionization pressure sensor that works on the principle of dielectric breakdown of gaseous medium. The high electric field (E_m = 1 MV/m) developed at the corners of the microtip produced dielectric breakdown of the medium, sufficient to produce ionization current at a relatively low bias voltage V_b <; 10 V. With increase in pressure, the availability of molecules in the vicinity of the micro-tip increased which when ionized by the application of V_b, produced enhanced ionization current through the device. The devices with cantilever lengths L = 50, 150, 250, 350, and 450 μm were designed with interelectrode spacing (d_int) of 1250 nm, which was further reduced by the application of suitable V_b to enhance the sensor performance. The device with L = 450 μm provides the widest dynamic range of 10^-4 - 10² mbar and the highest sensitivity of 2.44 μA/mbar with power consumption of 1.32 × 10^-1 μW at 10 V, which is 10⁴ times lower than previously reported device. The device offers a service life of 60 cycles assuming a tolerance of 10% in device performance.