Dielectric Breakdown-Assisted Corona Discharge-Based Pressure Sensor Using Poly-Si Microtips

Abstract

We report the development of low-power, dielectric breakdown-assisted corona discharge (CD)-based ionization pressure sensor for low-to-high vacuum measurements. The device possesses a reduced interelectrode spacing $d_{\mathrm{ int}}$ ( $= 1.25~\mu \text{m}$ under unbiased condition) and utilizes sharp microtip corners to generate electric field $E \,\, >$ dielectric breakdown field of the air $E_{b}$ (=3 MV/m) at low bias voltage $V_{b}> 2$ V. $E$ developed at the microtips ionizes the air molecules through dielectric breakdown of the intervening medium to produce ionization current, which obeys the modified CD current expression. The CD current has power law dependence on pressure and is utilized in the development of pressure sensor. Three variants of devices with single $(T_{1})$ microtip, 50 $(T_{50})$ microtips, and 100 $(T_{100})$ microtips are fabricated using the surface micromachining technique, and their performance is investigated and compared. Enhanced sensor performance is obtained for the device with an increased number of microtips $J$ . Our proposed device $T_{100}$ offers a wide dynamic range of $10^{-4} \,\, -50$ mbar and a high sensitivity of $2.03~\mu \text{A}$ /mbar and consumes low power of $0.34~\mu \text{W}$ .