Effect of membrane to heater ratio on the performance of square microhotplate

Square microhotplates are employed in wide application areas. An improvement in the performance of microhot-plate will be essential for improving the efficiency of the overall system. Selection of a proper Membrane to Heater Ratio (MHR) is critical for the performance of square membrane. The key parameters such as power, uniformity, mechanical reliability and response time are affected by the MHR value. In this paper, the effect of MHR on these parameters is systematically analyzed and the tradeoffs that exist among them are identified. With large MHR value (MHR=7), improvements of 44% and 56.5% have been achieved in power and uniformity respectively. However, the vertical deflection has increased from 2.1 μm (with MHR=2) to 7.3 μm (with MHR=7). The time response has also been deteriorated with large MHR value. The time response has increased from 0.37 ms (with MHR=2) to 2.5 ms (with MHR=7). A study of such tradeoffs between performance parameters are crucial in deciding the MHR of a square membrane. The final MHR can be decided by the prime requirement of an application area.