Study of MEMS Thermoresistive Gas Flow Sensors with Varied Thin-film Resistor Structures

Microelectromechanical systems (MEMS) gas flow sensors offer numerous advantages, including compact size, low power consumption, and high accuracy, making them indispensable in various applications. This paper presents the design and parametric study of thermoresistive gas flow sensors featuring distinct thin-film resistor structures. Through numerical simulations, we investigated the influence of these structures on sensor performance, focusing on parameters such as heater/sensor placement and length-to-width aspect ratio. Subsequently, we fabricated two types of MEMS thermoresistive gas flow sensors using standard microfabrication techniques. Performance evaluation of the packaged sensors was conducted under varying air flow rates. The measured results exhibited close agreement with simulation data, validating the efficacy of our model. Notably, the resistor with a lower length-to-width aspect ratio demonstrated a relatively high sensitivity of 5.4 $\mathrm{mV} /$ SLPM and a limit of detection (LOD) of 1 sccm. Our study contributes to the advancement of MEMS gas flow sensor technology, providing valuable insights into optimal design parameters, enhancing the efficacy and reliability of future sensor development efforts.