Abstract : Traditional metal oxide gas sensors are commonly used to measure flammable hydrocarbon gases and other toxic gases. However, they suffer from two drawbacks: (a) high operating temperature (not less than 300°C) and (b) high power consumption (greater than 1 watt). A silicon-based micro-metal oxide gas sensor under development overcomes these drawbacks. A significant portion of the power consumption of micromechanical gas sensors comprises various heat losses conducted through the silicon substrate, transferred to the air through all contact surfaces and radiation. The thermal characteristics of micromechanical metal oxide gas sensors need to be optimized for low power consumption by appropriately controlling the temperature distribution through the sensing layer and transient response. However, the microheater in MEMS metal oxide gas sensors has not yet been optimized. In this paper, we have developed a method (software) for designing and optimizing microheaters in MEMS gas sensors. Using this software, the power required to reach a certain temperature and the temperature distribution of the active layer can be estimated. Keywords : MEMS metal oxide gas sensor; microheater; thermal analysis; power optimization 1 Introduction Semiconductor metal oxides such as tin oxide, zinc oxide, and titanium dioxide have long been used to detect toxic (CO) and flammable gases (methane) by changes in conductivity. Raising the temperature of the sensing layer for sensitive gases to a certain value (typically 300-450°C) requires a significant amount of energy. Before the advent of micromechanical structures or MEMS, gas sensors (primarily ceramic-based) already exhibited high power consumption (typically 500mW - 2W) due to their excessive heat generation. Furthermore, their response time was extremely fast. Microheaters were designed and optimized for use with them. However, with the development of thermal isolation technology between MEMS and the sensing element and substrate, this power consumption has been reduced to only about 30-150 megawatts. Embedded heaters maintain the sensitive metal oxide layer at a certain temperature (where the sensitivity of the metal oxide in the sensor is highest), ultimately leading to high power consumption. For defined thermal characteristics, there are some software programs, such as ANSYS and Coventorware using the finite element method (FEM). However, these software programs are very expensive and therefore not widely applicable. This paper proposes a new design method to analyze power consumption and thermal characteristics. In this paper, we reveal the heat transfer theory based on fundamental thermodynamic equations. The results, based on this theory, demonstrate the effectiveness of some sampled programs, and the findings obtained through coventorware have been verified. This convenient and inexpensive method allows anyone to optimize power consumption at a specific sensitive temperature (determining the required power consumption to reach that temperature). [Full text available for download: Optimized Design of Microheaters in Smart MEMS Gas Sensors]