Thermo-Resistive Platinum Thin Film Hydrogen Gas Sensor Fabricated by MEMS Techniques

Abstract

Thermo-resistive platinum(Pt) thin film sensor was produced using Micro Electro Mechanical Systems (MEMS) fabrication techniques. The sensor design incorporated resistor elements that would facilitate the temperature-resistance characteristics and mechanisms of Pt based thin film thermo-resistors. The sensor was fabricated with lift-off process that allowed the dual sensing surface area. Furthermore, the dual sensing surfaces ensured faster response to hydrogen gas. To increase the catalytic reaction comparing with at the room temperature, the sensor was heated to a specified temperature by applying the current to a Pt thin film. The catalytic reaction took place when the heated sensor came into the contact with hydrogen. Additionally, the differential Pt thin film hydrogen gas sensor was also developed. This gas sensor was able to compensate the changes in the external environment such as temperature, moisture, etc. The fabricated hydrogen sensor detected the concentration of hydrogen gas in air from 2% to 9%.