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

Abstract

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} 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 $450~\mu \text{m}$ were designed with interelectrode spacing ( ${d}_{\textrm {int}} )$ of 1250 nm, which was further reduced by the application of suitable $V_{b}$ to enhance the sensor performance. The device with $L=450~\mu \text{m}$ provides the widest dynamic range of $10^{\mathrm {\mathbf {-4}}}-10^{\mathrm {\mathbf {2}}}$ mbar and the highest sensitivity of 2.44 $\mu \text{A}$ /mbar with power consumption of $1.32\times 10^{-1}~\mu \text{W}$ at 10 V, which is $10^{4}$ times lower than previously reported device. The device offers a service life of 60 cycles assuming a tolerance of 10% in device performance.