Differential Thermal Conductivity Hydrogen Sensor

In this work, a thermal conductivity sensor for the detection of hydrogen in fuel cell applications is presented. The sensor uses a differential measuring concept with two cavities combined on one semiconductor-die where one of those cavities is hermetically sealed and filled with nitrogen as a reference gas. The sensors were characterized with hydrogen concentrations between 0 and 3.5 % at different heater temperatures. A 3σ-noise level of 0.06 % hydrogen was achieved with the prototype sensor.