Electro thermal analysis and fabrication of low cost microheater using a nickel alloy for low temperature MEMS based gas sensor application

A stable and low power heating characteristics of a microheater are very important for the gas sensor platform. In this paper, we present a complete electrothermal and coplanar structure of a microheater for MEMS based gas sensor platform using a low cost nickel alloy Dilver PI (alloy of Ni, Co, Fe) having high resistivity 49*10-8Ωm and high yield stress 680MPa with low thermal conductivity 17.5W/m/°C. A comparative study has also been made with six different types of heater structures. Thermal electrical analysis was done using finite element modeling of Intellisuite 8.2. Microheater device of size 5mm × 5mm with a 50μ thick membrane of size 2mm*2mm are fabricated using a single lithographic mask. The maximum temperature of 200°C with a distribution of ± (2-3) % over the entire microheater membrane region has been achieved with 5V excitation. The power consumption 146 mW has been achieved.